User:Emijrp/All Human Knowledge

This is an essay. It expresses the opinions and ideas of some Wikidata contributors, but may not have wide support. Feel free to edit this page or use the discussion page.

The Great Library of Alexandria in Egypt
Natural History by Pliny the Elder
Etymologiae by Isidore of Seville
Speculum Maius by Vincent of Beauvais
Denis Diderot contributor to Encyclopédie
Advertisement for the Encyclopædia Britannica 11th edition
Internet Archive PetaBox, designed to store one petabyte (a million gigabytes) of information^[1]

Knowledge as a social good and the Library of Babel in Wikimanía 2009. (Watch on YouTube)

The idea of compiling all human knowledge into a single work, though not in a single place,^[3] is highly compelling. In this essay, we attempt to examine how many articles would be required to cover the sum of all human knowledge. As of July 2026, English Wikipedia hosts 7,206,436 articles,^[4] and the wider Wikimedia ecosystem includes 122,364,070 items in Wikidata,^[5] 144,280,788 files in Wikimedia Commons,^[6] 950,425 forms of life in Wikispecies,^[7] 8,913,723 entries in Wiktionary,^[8] and 1,115,374 texts in Wikisource.^[9] Yet all of these projects remain far from complete.

Of course, there are already articles for all the countries of the world and most of their administrative divisions, millions of biographies, hundreds of thousands of geographical features, tens of thousands of creative works such as books and films. However, examining these and other topics with an exhaustive focus still reveals millions of missing articles.

"This is a work that cannot be completed except by a society of men of letters and skilled workmen, each working separately on his own part, but all bound together solely by their zeal for the best interests of the human race and a feeling of mutual good will." –Denis Diderot, Encyclopédie (1751–1766)

Wikipedia, Wikidata, and their sister projects such as Wikimedia Commons have different standards of notability. There have been heated debates about notability, especially on Wikipedia, and although notability threshold has decreased over the years, it is still stricter on Wikipedia than on Wikidata.

In this essay, it is assumed that any topic described in a reputable source deserves a place in the Wikimedia projects, whether it is a prominent ancient Greek philosopher or an apparently insignificant star in a galaxy millions of light-years away. With that in mind, this page still under expansion, estimates the potential number of Wikidata items at 9,025,925,491.

In a more exhaustive approach, where even entities that are known to exist but have not yet been described are counted, the estimate increases by several orders of magnitude, reaching up to 1,000,000,000,000,000,000,000,000,000 (10²⁷). Finally, if notability requirement is removed, then the theoretical number of items becomes $\infty$ infinite.

As of 2026, Wikipedia and its sister projects are backed up in mirrors around the world (hot storage),^[10]^[11] in the Internet Archive (warm storage)^[12]^[13]^[14] and in the Arctic World Archive (cold storage).^[15]^[16] Although more backups are always desirable, a full off-site mirror of Wikimedia Commons (over 999 TB) has yet to be created.

You are welcome to improve this page, be bold!

Background

Many individuals have devoted their lives to various efforts of knowledge compilation and preservation. Some inspiring examples include Vivian Maier, a nanny who took 150,000 photographs during her lifetime primarily of people and architecture;^[17] Paul Mawhinney, who archived a copy of every album sold, building a collection of 3 million vinyl records;^[18] Henry Spencer, a computer scientist who preserved over 2 million Usenet messages on magnetic tapes^[19] and Marion Stokes, who recorded hundreds of thousands of hours of television news footage over a span of 35 years.^[20]

"Like all persons of the Library, I have traveled in my youth; I have wandered in search of a book, perhaps the catalogue of catalogues..." –Jorge Luis Borges, The Library of Babel (1941)

Before Wikipedia, there were many attempts to compile all human knowledge. Some examples, sorted by date, include:

Library of Alexandria (3rd century BC) in Egypt, the most famous ancient attempt to gather all written knowledge in one place.
Natural History (AD 77–79) by Pliny the Elder, a 37-book Roman encyclopedia covering the natural world.
Etymologiae (7th century) by Isidore of Seville, the dominant medieval encyclopedia in Western Europe.
De universo (9th century) by Rabanus Maurus, a Carolingian encyclopedic work synthesizing theology and natural philosophy.
Speculum Maius (13th century) by Vincent of Beauvais, a massive medieval encyclopedia intended to summarize all knowledge of the time.
Yongle Encyclopedia (1403–1408) by Ming dynasty, the largest encyclopedia of its era, containing thousands of volumes.
Bibliotheca universalis (1545–1549) by Conrad Gessner, a universal bibliography attempting to list all books ever printed.
The abstracting and indexing project (17th century) by Gottfried Wilhelm Leibniz, a visionary plan to create a universal catalog of all human knowledge.
Encyclopédie (1751–1772) by Denis Diderot and Jean Le Rond d'Alembert, the Enlightenment's most influential encyclopedia.
Mundaneum (1910) by Paul Otlet and Henri La Fontaine, an attempt to create a universal repository of all knowledge using index cards.
Encyclopædia Britannica 11th edition, a landmark modern encyclopedia known for its scholarly depth.
And more recently Interpedia (1993) by Rick Gates, Internet Archive (1996) by Brewster Kahle and Wikidata (2012).

Also, hypothetical cases exist: Encyclopedia Galactica (1980) by Carl Sagan in Cosmos, Permanent World Encyclopaedia (1936–1938) by H. G. Wells and Memex (1945) by Vannevar Bush. Finally, there are imaginary examples too: "The Universal Library" (1901) by Kurd Lasswitz, "The Total Library" essay and The Library of Babel (1941) by Jorge Luis Borges, Encyclopedia Galactica (1942) in Foundation series by Isaac Asimov and the Akashic records.

Furthermore, there are thousands of archives, libraries, and museums around the world that preserve human knowledge in many formats: books, manuscripts, academic journals, newspapers, magazines, sound and music recordings, video recordings, play-scripts, patents, databases, maps, postage stamps, prints, drawings and more. Some of the largest ones are: Library of Congress (178 million items^[21]), British Library (170 million items^[22]), Russian State Library (50 million items^[23]), National Diet Library (35 million items^[24]), National Library of China (31 million items^[25]) and Bibliothèque nationale de France (31 million items^[26]).

"There is no practical obstacle whatever now to the creation of an efficient index to all human knowledge, ideas and achievements, to the creation, that is, of a complete planetary memory for all mankind." –H. G. Wells, World Brain (1937)

For completeness regarding Wikipedia's sister projects, see § Sister projects. For an estimate of lost or irrecoverable knowledge, see § Lost knowledge and Wikipedia:There is a deadline.

Summary

Domain	Branch	Progress^{[n 1]}	Topics
Epistemology	Epistemology	`Enwiki:` 93,245 `Commons:` 16,400 `Wikidata:` 196,949 `Estimate:` 21,111,000	Branches of science · Academic disciplines · Fields of study · Topics · Research questions · Hypotheses
Arts
	Architecture	`Enwiki:` 285,268 `Commons:` 1,032,623 `Wikidata:` 5,283,589 `Estimate:` 159,591,136	Aquaria · Aqueducts · Bridges · Bullrings · Castles · Cemeteries · Dams · Fountains · Gates · Monuments · Horse racing venues · Hospitals · Hotels · Houses · Lighthouses · Military bases · Mines · Movie theaters · Observatories · Palaces · Parks · Places of worship · Power stations · Prisons · Pyramids · Research stations · Reservoirs · Schools · Shopping centers · Skyscrapers · Squares · Stadiums · Streets · Theatres · Towers · Tunnels · Universities · Watermills · Weather stations · Windmills · Zoos
	Cinema, television and radio	`Enwiki:` 317,564 `Commons:` 27,036 `Wikidata:` 1,053,133 `Estimate:` 11,547,436	Movies · TV episodes · TV stations · TV channels · TV programs · Radio stations
	Literature	`Enwiki:` 114,476 `Commons:` 35,359 `Wikidata:` 2,826,501 `Estimate:` 1,612,352,563	Academic journals · Journal articles · Thesis · Bibliographies · Comics · Dictionaries · Dictionary entries · Encyclopedias · Encyclopedia articles · Books · Editions · Codices · Incunabulas · Manuscripts · Speeches · Fictional entities · Magazines · Newspapers · Poetry · Theatre · Verses of texts
	Performing arts	`Enwiki:` 171,760 `Commons:` 4,414 `Wikidata:` 414,430 `Estimate:` 105,075,849	Musical instruments · Albums · Lyrics · Songs
	Visual arts	`Enwiki:` 19,959 `Commons:` 90,965 `Wikidata:` 1,832,547 `Estimate:` 210,001,000	Cave paintings · Drawings · Geoglyphs · Lithographies · Mosaics · Murals · Paintings · Petroglyphs · Photographies · Sculptures
Geography
	Human geography	`Enwiki:` 335,293 `Commons:` 162,585 `Wikidata:` 1,836,224 `Estimate:` 36,126,000	Sovereign states · Administrative divisions · Micronations · Neighborhoods
	Physical geography	`Enwiki:` 122,049 `Commons:` 93,627 `Wikidata:` 2,079,234 `Estimate:` 38,738,935	Continents · Canals · Caves · Deserts · Oases · Forests · Glaciers · Hills · Islands · Lakes · Mountains · Mountain ranges · Rivers · Seas · Volcanoes
History
	Calendars and events	`Enwiki:` 544,691 `Commons:` 160,824 `Wikidata:` 2,273,180 `Estimate:` 5,240,500	Calendars · Calendar days · Events · Disasters
	GLAM	`Enwiki:` 53,159 `Commons:` 70,592 `Wikidata:` 1,305,414 `Estimate:` 3,005,904,000	Archives · Libraries · Museums · Collections · Items of collections
	Heraldry and vexillology	`Enwiki:` 2,521 `Commons:` 4,338 `Wikidata:` 28,936 `Estimate:` 6,090,000	Coats of arms · Flags
	Numismatics and philately	`Enwiki:` 2,039 `Commons:` 1,907 `Wikidata:` 96,569 `Estimate:` 2,220,000	Banknotes · Coins · Medals · Stamps
	Politics	`Enwiki:` 52,604 `Commons:` 4,830 `Wikidata:` 100,509 `Estimate:` 2,200,000	Opinion polls · Elections · Referendums · Terms of office
Science
	Astronomy	`Enwiki:` 43,342 `Commons:` 9,125 `Wikidata:` 7,492,118 `Estimate:` 1,895,239,352	Universe · Galaxy voids · Galaxy filaments · Galaxy superclusters · Galaxy clusters · Galaxies · Interestellar clouds · Stars · Black holes · Pulsars · Supernovae · Exoplanets · Natural satellites · Asteroids · Comets
	Biology	`Enwiki:` 522,296 `Commons:` 275,039 `Wikidata:` 6,150,366 `Estimate:` 459,149,694	Domains · Kingdoms · Phyla · Classes · Orders · Families · Genera · Species · Cell lines · Genes · Proteins · Non-coding RNA
	Chemistry and physics	`Enwiki:` 2,253 `Commons:` 1,753 `Wikidata:` 149,631 `Estimate:` 441,400,500	Chemical compounds · Chemical reactions · Crystal structures · Subatomic particles
	Mathematics	`Enwiki:` 5,414 `Commons:` 28,222 `Wikidata:` 557,055 `Estimate:` 2,410,000	Algorithms · Numbers · Prime numbers · Integer sequences
	Medicine	`Enwiki:` 5,537 `Commons:` 1,424 `Wikidata:` 795,678 `Estimate:` 763,453	Clinical trials · Diseases · Drugs · Medical procedures · Psychology · Psychiatry
	Research	`Enwiki:` 16,751 `Commons:` 3,683 `Wikidata:` 593,915 `Estimate:` 18,200,000	Academic labs · Datasets · Research groups · Research projects
Society
	Biography	`Enwiki:` 2,994,248 `Commons:` 1,240,203 `Wikidata:` 12,257,366 `Estimate:` 164,000,000	Biographies · Given name · Family names · Titles · Awards
	Gastronomy	`Enwiki:` 5,938 `Commons:` 5,249 `Wikidata:` 50,840 `Estimate:` 6,000,000	Cuisine · Food · Recipes · Drinks
	Language	`Enwiki:` 10,150 `Commons:` 13,981 `Wikidata:` 181,121 `Estimate:` 314,834	Languages · Writing systems · Unicode
	Organization	`Enwiki:` 173,191 `Commons:` 301,620 `Wikidata:` 8,382,346 `Estimate:` 570,133,200	Civilizations · Business · Crafts · Economics · Hobbies · Law · Legal cases · Organizations · Positions
	Philosophy	`Enwiki:` 10,575 `Commons:` 2,445 `Wikidata:` 65,127 `Estimate:` 100,000	Philosophy
	Religion, mythology and folkore	`Enwiki:` 2,902 `Commons:` 1,419 `Wikidata:` 11,335 `Estimate:` 285,138	Religions · Religion concepts · Sacred texts · Cultures · Folklore · Mythologies · Pseudoscience
	Sports	`Enwiki:` 210,760 `Commons:` 34,854 `Wikidata:` 545,362 `Estimate:` 11,010,000	Sports · Sports seasons · Sports matches
Technology
	Computing	`Enwiki:` 19,123 `Commons:` 4,507 `Wikidata:` 10,554,760 `Estimate:` 970,000	Artificial intelligence · Hardware · File formats · Malware · Software · Websites
	Engineering	`Enwiki:` 20,633 `Commons:` 4,763 `Wikidata:` 455,751 `Estimate:` 191,025,000	Engineering · Patents · Technical standards · Trademarks
	Transport	`Enwiki:` 172,083 `Commons:` 415,885 `Wikidata:` 1,346,666 `Estimate:` 39,479,330	Airports · Bus stations · Heliports · Means of transport · Parkings · Ports · Railway lines · Train stations · Roads · Traffic signs
Special pages	Special pages	`Enwiki:` 3,729,708 `Commons:` 3,552,577 `Wikidata:` 9,242,608 `Estimate:` 9,246,571	Categories · Disambiguations · Lists · Portals · Templates
Total (described)		`Enwiki:` 10,059,532 `Commons:` 7,602,249 `Wikidata:` 78,159,260 `Estimate:` 9,025,925,491	Number of entities described in reputable sources.
Total (non-described)		`Estimate:` 1,000,000,000,000,000, 000,000,000,000 (10²⁷)	Number of entities known to exist but not described yet.
Total (non-notable)		`Estimate:` $\infty$ infinite	Number of entities after including non-notable ones too.

Epistemology

Epistemology examines the nature, origin, and limits of knowledge. Also called the theory of knowledge, it explores different types of knowledge, such as propositional knowledge about facts, practical knowledge in the form of skills, and knowledge by acquaintance as a familiarity through experience. Epistemologists study the concepts of belief, truth, and justification to understand the nature of knowledge. To discover how knowledge arises, they investigate sources of justification, such as perception, introspection, memory, reason, and testimony.

Topic	Progress	Notes, sources and references
branch of science (Q2465832): field of scientific study	`Enwiki:` 1,543 `Commons:` 117 `Wikidata:` 2,578 `Estimate:` 1,000	A branch of science is a specialized field of study within science, each focusing on a particular aspect of the natural world, abstract systems, or human behavior. According to available estimates, there are approximately 1,000 branches of science.^[27]
academic discipline (Q11862829): academic field of study or profession	`Enwiki:` 5,458 `Commons:` 815 `Wikidata:` 12,890 `Estimate:` 10,000	An academic discipline is a formally organized field of study taught and researched in universities. It has its own body of knowledge, methods, theories, and community of scholars who advance the field. According to available estimates, there are approximately 10,000 academic disciplines.^[27]
field of study (Q1047113): field limited to a specific area of knowledge; specialization in an occupation or branch of learning; a specific use	`Enwiki:` 42,209 `Commons:` 7,619 `Wikidata:` 75,430 `Estimate:` 100,000	A field of study is a distinct area of knowledge that groups together related questions, methods, and subjects. According to available estimates, there are approximately 100,000 fields of study.^[27]
topic (Q26256810): topic or area addressed by a work or set of works	`Enwiki:` 43,142 `Commons:` 7,794 `Wikidata:` 80,453 `Estimate:` 1,000,000	A topic is a specific subject within a field of study. According to available estimates, there are approximately 1 million topics.^[27]
research question (Q1438033): question that a research project sets out to answer	`Enwiki:` 1 `Commons:` 0 `Wikidata:` 1 `Estimate:` 5,000,000	A research question is a precise question a study aims to answer. According to available estimates, there are approximately 5 million research questions.^[27]
hypothesis (Q41719): proposed explanation for an observation, phenomenon, or scientific problem	`Enwiki:` 892 `Commons:` 55 `Wikidata:` 25,597 `Estimate:` 15,000,000	A hypothesis is a testable proposed explanation. According to available estimates, there are approximately 15 million hypotheses.^[27]
Total	`Enwiki:` 93,245 `Commons:` 16,400 `Wikidata:` 196,949 `Estimate:` 21,111,000

Arts

The arts are composed of many endeavors (or artforms) united by their employment of the creative impulse. (Main articles: Outline of the visual arts, Element of art and Principles of art)

Architecture

Architecture is both the process and product of planning, designing and construction. Architectural works, in the material form of buildings, are often perceived as cultural and political symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements. (Main articles: Outline of architecture and Lists of buildings and structures) (Main categories: Category:Architecture lists and Category:Lists of buildings and structures) (For libraries, museums, archives, see § GLAM) (For transport infrastructure, see § Transport) (Note: some of these items may overlap)

Topic	Progress	Notes, sources and references
public aquarium (Q2281788): facility and institution that exhibits live aquatic animals and plants in large tanks for the public to view, learn about, and appreciate	`Enwiki:` 266 `Commons:` 414 `Wikidata:` 572 `Estimate:` 1,100	According to available sources, there are approximately 1,100 aquaria worldwide.^[28]
aqueduct (Q474): structure constructed to convey water	`Enwiki:` 236 `Commons:` 726 `Wikidata:` 1,846 `Estimate:` 30,000	According to available estimates, there are approximately 30,000 aqueducts worldwide, including Roman, Greek and Islamic aqueducts, and Persian qanats.^[27]
bridge (Q12280): structure that spans and provides a passage over a road, railway, river, or some other obstacle	`Enwiki:` 9,434 `Commons:` 34,399 `Wikidata:` 72,689 `Estimate:` 15,000,000	There are at least 614,000 bridges in the United States,^[29] 39,500 bridges on federal roads in Germany,^[30] and 17,500 road bridges in the Czechia alone.^[31] This suggests roughly 500–2,000 inhabitants per bridge, which implies a global total of approximately 5–15 million bridges.
bullring (Q1193438): arena where bullfighting is performed	`Enwiki:` 60 `Commons:` 402 `Wikidata:` 859 `Estimate:` 3,500	According to available sources, there are approximately 3,500 bullrings worldwide.^[32]
castle (Q23413): type of fortified structure built in Europe, Asia and the Middle East during the Middle Ages by nobility	`Enwiki:` 6,472 `Commons:` 16,336 `Wikidata:` 34,611 `Estimate:` 52,000	According to available estimates, there are approximately 52,000 castles worldwide.^[27]
cemetery (Q39614): place of burial	`Enwiki:` 4,961 `Commons:` 29,769 `Wikidata:` 449,179 `Estimate:` 1,200,000	According to available estimates, there are approximately 1.2 million cemeteries worldwide.^[27]
dam (Q12323): barrier that impounds water or underground streams	`Enwiki:` 5,447 `Commons:` 3,992 `Wikidata:` 83,368 `Estimate:` 800,000	According to available sources, by 1997 there were about 800,000 dams worldwide, including 40,000 that were over 15 m high.^[33]
fountain (Q483453): piece of architecture that ejects water	`Enwiki:` 526 `Commons:` 8,527 `Wikidata:` 36,235 `Estimate:` 140,000	According to available estimates, there are approximately 140,000 fountains worldwide.^[27]
gate (Q53060): point of entry to a space enclosed by building, wall or fence	`Enwiki:` 595 `Commons:` 4,572 `Wikidata:` 13,035 `Estimate:` 15,000	According to available estimates, there are approximately 15,000 gates worldwide.^[27]
heritage (Q2434238): property, custom, or other material, immaterial or natural object inherited from previous generations, and conserved for its importance for future generations	`Enwiki:` 16,651 `Commons:` 93,382 `Wikidata:` 602,809 `Estimate:` 5,000,000	According to available estimates, there are approximately 1–5 million monuments worldwide.^[27]
horse racing venue (Q11822917): venue used in horse racing	`Enwiki:` 359 `Commons:` 348 `Wikidata:` 939 `Estimate:` 1,000	According to available estimates, there are approximately 1,000 horse racing venues worldwide.^[27]
hospital (Q16917): health care facility	`Enwiki:` 7,932 `Commons:` 7,498 `Wikidata:` 47,964 `Estimate:` 215,977	According to available sources, there are 16,500 hospitals worldwide.^[34] Microsoft Copilot provides a higher estimate of roughly 66,000 hospitals globally.^[27] Statista reports an even larger figure, estimating 215,977 hospitals worldwide.^[35]
hotel (Q27686): business enterprise that provides indoor lodging in a single location paid on a short-term basis	`Enwiki:` 6,883 `Commons:` 20,732 `Wikidata:` 164,166 `Estimate:` 817,196	According to available sources, there are approximately 817,196 hotels and other accommodation establishments worldwide.^[36]^[37]
house (Q3947): building usually intended for living in	`Enwiki:` 28,607 `Commons:` 127,082 `Wikidata:` 515,787 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million historic houses worldwide.^[27]
lighthouse (Q39715): structure designed to emit light to aid navigation	`Enwiki:` 2,404 `Commons:` 4,055 `Wikidata:` 10,003 `Estimate:` 24,400	According to available sources, there are 24,400 lighthouses worldwide.^[38]
military base (Q245016): facility directly owned and operated by or for the military	`Enwiki:` 4,640 `Commons:` 3,429 `Wikidata:` 12,569 `Estimate:` 15,000	According to available estimates, there are approximately 15,000 military bases worldwide.^[27]
mine (Q820477): place for the extraction of minerals	`Enwiki:` 3,099 `Commons:` 3,360 `Wikidata:` 56,453 `Estimate:` 500,000	According to available estimates, there are approximately 300,000–500,000 mines worldwide.^[27]
movie theater (Q41253): venue, usually a building, for viewing films	`Enwiki:` 2,375 `Commons:` 5,075 `Wikidata:` 58,723 `Estimate:` 200,000	According to available estimates, there are approximately 200,000 movie theaters worldwide.^[27]
observatory (Q62832): location used for observing terrestrial or celestial events	`Enwiki:` 1,120 `Commons:` 917 `Wikidata:` 3,969 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 observatories worldwide.^[27]
palace (Q16560): grand residence, especially a royal or episcopal residence	`Enwiki:` 2,547 `Commons:` 11,516 `Wikidata:` 21,061 `Estimate:` 25,000	According to available estimates, there are approximately 25,000 palaces worldwide.^[27]
park (Q22698): permanently dedicated recreation area, often open to the public and generally characterized by natural, historic, or landscape features	`Enwiki:` 20,016 `Commons:` 30,241 `Wikidata:` 131,804 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million parks worldwide.^[27]
structure of worship (Q1370598): specially designed structure for use in worshipping	`Enwiki:` 49,627 `Commons:` 315,230 `Wikidata:` 889,328 `Estimate:` 25,000,000	According to available estimates, there are approximately 25 million places of worship worldwide.^[27] As of 2011, the Catholic Church had 3,068 churches of cathedral and co-cathedral status around the world.^[39] Estimations of churches worldwide range from 250,000^[40] to 3,700,000,^[41] with 450,000 only in USA.^[42] There are 2.5 million mosques in the world.^[43]^[44]
power station (Q159719): facility generating electric power	`Enwiki:` 5,408 `Commons:` 4,472 `Wikidata:` 30,267 `Estimate:` 182,400	According to available sources, there are approximately 182,400 power stations worldwide.^[45]
prison (Q40357): place in which people are, for legal reasons, physically confined and usually deprived of a range of personal freedoms	`Enwiki:` 3,123 `Commons:` 2,180 `Wikidata:` 11,576 `Estimate:` 25,000	According to available sources, there are approximately 4,575 prisons in the United States and 1,029 in Russia.^[46] According to available estimates, there are approximately 25,000 prisons, jails, and detention facilities worldwide.^[27]
pyramid (Q12516): structure whose shape is roughly that of a pyramid in the geometric sense	`Enwiki:` 117 `Commons:` 124 `Wikidata:` 195 `Estimate:` 5,000	According to available estimates, there are approximately 5,000 pyramids worldwide.^[27]
research station (Q195339): station that is built for the purpose of conducting scientific research	`Enwiki:` 258 `Commons:` 201 `Wikidata:` 651 `Estimate:` 25,000	According to available estimates, there are approximately 25,000 research stations worldwide.^[27]
reservoir (Q131681): artificial lake impounded using a dam or lock to store water	`Enwiki:` 3,237 `Commons:` 4,109 `Wikidata:` 29,280 `Estimate:` 556,063	According to available sources, there are 556,063 reservoirs worldwide.^[47]
school (Q3914): institution for the education of students by teachers	`Enwiki:` 50,194 `Commons:` 27,894 `Wikidata:` 1,033,694 `Estimate:` 5,500,000	According to available estimates, there are approximately 5.5 million schools worldwide.^[27]
shopping center (Q11315): complex of shops	`Enwiki:` 3,986 `Commons:` 4,953 `Wikidata:` 10,200 `Estimate:` 116,000	According to available estimates, there are approximately 116,000 shopping centers worldwide.^[27]
skyscraper (Q11303): very tall building	`Enwiki:` 3,200 `Commons:` 3,248 `Wikidata:` 5,150 `Estimate:` 94,000	According to available sources, there are 94,000 skyscrapers worldwide.^[48]
square (Q174782): open public spaces in cities or towns, usually rectilinear, surrounded by buildings, and often located at the junction of two or more thoroughfares	`Enwiki:` 2,294 `Commons:` 18,752 `Wikidata:` 27,427 `Estimate:` 117,000	According to available estimates, there are approximately 117,000 squares worldwide.^[27]
stadium (Q483110): place or venue for (mostly) outdoor sports, concerts, or other events	`Enwiki:` 8,027 `Commons:` 5,835 `Wikidata:` 14,993 `Estimate:` 11,500	According to available sources, there are 11,500 stadiums worldwide. 689 in Africa, 1,200 in Asia, 286 in Central America, 4,268 in Europe, 527 in Middle East, 2,869 in North America, 284 in Oceania and 1,417 in South America.^[49]
street (Q79007): public thoroughfare in a built environment like a village or city	`Enwiki:` 5,492 `Commons:` 200,101 `Wikidata:` 759,716 `Estimate:` 100,000,000	According to available estimates, there are approximately 100 million streets worldwide.^[27]
theatre building (Q24354): building for performances by actors	`Enwiki:` 4,620 `Commons:` 7,775 `Wikidata:` 21,077 `Estimate:` 25,000	According to available estimates, there are approximately 25,000 theatres worldwide.^[27]
tower (Q12518): structure with height greater than width	`Enwiki:` 2,272 `Commons:` 14,713 `Wikidata:` 37,195 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million towers worldwide.^[27]
tunnel (Q44377): underground passageway	`Enwiki:` 1,414 `Commons:` 3,283 `Wikidata:` 21,973 `Estimate:` 50,000	According to es:Anexo:Túneles de España, in Spain there are 400 road tunnels and 1700 railway tunnels. According to available estimates, there are approximately 50,000 tunnels worldwide.^[27]
university (Q3918): an institution of tertiary education and research which awards academic degrees in several academic disciplines	`Enwiki:` 14,434 `Commons:` 3,978 `Wikidata:` 22,205 `Estimate:` 20,000	According to available sources, there are 20,000 universities worldwide.^[50]
watermill (Q185187): structure that uses a water wheel or turbine to drive a mechanical process	`Enwiki:` 242 `Commons:` 3,074 `Wikidata:` 7,798 `Estimate:` 250,000	According to available estimates, there are approximately 250,000 historic watermills worldwide.^[27]
weather station (Q190107): set of sensors that record and provide physical measurements and meteorological parameters	`Enwiki:` 48 `Commons:` 155 `Wikidata:` 32,398 `Estimate:` 300,000	According to available estimates, there are approximately 300,000 weather stations worldwide.^[27]
windmill (Q38720): machine that converts the energy of wind into rotational energy by means of adjustable sails	`Enwiki:` 608 `Commons:` 3,331 `Wikidata:` 4,978 `Estimate:` 250,000	According to available estimates, there are approximately 250,000 historic windmills worldwide.^[27]
zoo (Q43501): collection of assorted wild animal species kept for purposes like: study, conservation and, or, commercial exhibition	`Enwiki:` 1,388 `Commons:` 2,126 `Wikidata:` 2,967 `Estimate:` 10,000	According to available sources, there are approximately 10,000 zoos worldwide.^[51]
list of building types (Q3634365): Wikimedia list article	`Enwiki:` 0 `Commons:` 0 `Wikidata:` 0 `Estimate:` 2,000	According to available estimates, there are approximately 2,000 building types.^[27]
architectural style (Q32880): visual characteristics of a building	`Enwiki:` 649 `Commons:` 317 `Wikidata:` 1,880 `Estimate:` 2,000	According to available estimates, there are approximately 2,000 architecture styles.^[27]
Total	`Enwiki:` 285,268 `Commons:` 1,032,623 `Wikidata:` 5,283,589 `Estimate:` 159,591,136

Cinema, television and radio

Cinematography is the art of motion picture photography. Television is a telecommunication medium for transmitting moving images and sound. Radio is the technology of communicating using radio waves. (This section excludes § Biographies) (This section excludes § Archives)

Topic	Progress	Notes, sources and references
film (Q11424): visual art work that simulates experiences and communicates ideas, stories, or emotions through moving images, generally synchronized with sound since the 1930s	`Enwiki:` 180,967 `Commons:` 19,656 `Wikidata:` 436,865 `Estimate:` 896,440	According to available sources, there are 742,038 movies and 154,402 TV movies.^[52]
short film (Q24862): any film not long enough to be considered a feature film	`Enwiki:` 0 `Commons:` 0 `Wikidata:` 0 `Estimate:` 1,141,132	According to available sources, there are 1,141,132 shorts.^[52]
television series episode (Q21191270): single installment of a television series	`Enwiki:` 16,462 `Commons:` 113 `Wikidata:` 188,423 `Estimate:` 9,576,996	According to available sources, there are 9,576,996 TV episodes.^[52]
television station (Q1616075): organization that transmits content on television	`Enwiki:` 6,797 `Commons:` 1,343 `Wikidata:` 10,904 `Estimate:` 20,000	According to available sources, there are 1,700+ TV stations (and 2,100+ low power) in USA.^[53] According to available estimates, there are approximately 20,000 TV stations worldwide.^[27]
television channel (Q2001305): terrestrial frequency or virtual number over which a television station or television network is distributed	`Enwiki:` 3,717 `Commons:` 657 `Wikidata:` 6,631 `Estimate:` 10,000	According to available sources, there are approximately 700 TV channels in India,^[54] 7,200 in Europe as of 2009 (UE 27 + Croatia and Turkey).^[55] According to available estimates, there are approximately 10,000 TV channels worldwide.^[27]
television program (Q15416): segment of audiovisual content intended for broadcast and streaming on television	`Enwiki:` 85,987 `Commons:` 4,118 `Wikidata:` 379,568 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million TV programs.^[27]
radio station (Q14350): organization for the production and transmission of radio programs	`Enwiki:` 23,634 `Commons:` 1,149 `Wikidata:` 30,742 `Estimate:` 44,000	According to available sources, there are 44,000 radio stations worldwide^[56] and according to Federal Communications Commission 14,000+ are in USA.^[53]
Total	`Enwiki:` 317,564 `Commons:` 27,036 `Wikidata:` 1,053,133 `Estimate:` 11,547,436

Literature

Literature is the art of written works. The word literature literally means: "things made from letters". Literature is commonly classified as having two major forms—fiction and non-fiction—and two major techniques—poetry and prose. (This section excludes § Biographies and § Libraries)

Topic	Progress	Notes, sources and references
academic journal (Q737498): peer-reviewed periodical relating to an academic discipline	`Enwiki:` 9,779 `Commons:` 1,215 `Wikidata:` 127,033 `Estimate:` 150,000	According to available sources, approximately 150,000 academic journals have been published.^[57] See also Journals cited by Wikipedia.
scholarly article (Q13442814): article in an academic publication, usually peer reviewed	`Enwiki:` 390 `Commons:` 57 `Wikidata:` 1,460 `Estimate:` 130,000,000	According to available sources, over 50 million journal articles have been published between 1665 and 2009.^[58] With publication rates increasing by about 5 million per year, the estimated total by 2026 is roughly 130 million articles. Number of records in different academic databases: ScienceOpen (91,000,000)^[59] Europe PubMed Central (48,000,000)^[60] Scholia (41,000,000)^[61] Internet Archive Scholar (35,000,000)^[62] Inspec (27,000,000)^[63] PubMed Central (12,100,000)^[64] Compendex (10,300,000)^[65] IEEE Xplore (5,500,000)^[66] Elsevier BIOBASE (4,100,000) Academic Search (3,000,000) arXiv (2,400,000)^[67] SciELO (230,000) See also Lists of important publications in science.
thesis (Q1266946): work by academic candidate	`Enwiki:` 0 `Commons:` 0 `Wikidata:` 34 `Estimate:` 7,464,811	The Open Access Theses and Dissertations database indexes 7,464,811 theses and dissertations from over 1,100 colleges, universities, and research institutions.^[68]
bibliography (Q1631107): list of books or documents relevant to a particular subject or author	`Enwiki:` 9,523 `Commons:` 472 `Wikidata:` 37,872 `Estimate:` 0	The total number of bibliographies ever published is unknown.
comic (Q1004): creative work in which images and text convey information such as narratives	`Enwiki:` 11,091 `Commons:` 517 `Wikidata:` 48,138 `Estimate:` 2,100,000	According to available sources, approximately 2.1 million comics have been issued.^[69]
dictionary (Q23622): collection of words and their meanings	`Enwiki:` 786 `Commons:` 318 `Wikidata:` 5,889 `Estimate:` 85,000	According to available sources, approximately 85,000 dictionaries have been published.^[70]
dictionary entry (Q1580166): part of a dictionary covering a specific word or phrase; the lexicographical information covered depends on the kind of the dictionary; single dictionary entry covers all senses of the word	`Enwiki:` 10 `Commons:` 15 `Wikidata:` 167,420 `Estimate:` 1,200,000,000	According to available estimates, roughly 300–1,200 million dictionary entries exist across all dictionaries.^[27]
encyclopedia (Q5292): type of reference work	`Enwiki:` 602 `Commons:` 501 `Wikidata:` 2,703 `Estimate:` 50,000	According to available sources, approximately 13,000 encyclopedias have been published.^[71] Microsoft Copilot provides a higher estimate of roughly 50,000 encyclopedias. Some of the most complete encyclopedias are Enciclopedia universal ilustrada europeo-americana (800,000 articles), Encyclopædia Britannica (100,000 articles), Encyclopédie (72,000 articles^[72]) and Oxford Reference Online (1,400,000 articles). Wikipedia:WikiProject Missing encyclopedic articles Wikipedia:Size comparisons Portal:Reference Works See more encyclopedias in Google Books and Internet Archive. See also List of encyclopedias by language, List of encyclopedias by branch of knowledge and List of online encyclopedias.
encyclopedia article (Q13433827): part of encyclopedia, sometimes considered as reference work by itself	`Enwiki:` 40 `Commons:` 46 `Wikidata:` 866,006 `Estimate:` 15,000,000	According to available estimates, approximately 5–15 million encyclopedia articles have been published (excluding Wikipedia).^[27]
book (Q571): medium for recording information (words or images) typically on bound pages or more abstractly in electronic or audio form	`Enwiki:` 4,743 `Commons:` 2,371 `Wikidata:` 75,765 `Estimate:` 50,000,000	According to available estimates, approximately 40–50 million unique books (not counting separated editions, translations or reprints) have been published.^[27]
version, edition or translation (Q3331189): specific version of a work, resulting from its edition, adaptation, or translation; set of substantially similar copies of a work (use with P31 ["instance of"])	`Enwiki:` 1,686 `Commons:` 7,930 `Wikidata:` 860,746 `Estimate:` 158,464,880	As of 2010, according to Google, there were 129,864,880 books (considering all editions separately).^[73] UNESCO estimates that 2.2 million new titles are published every year, so there are roughly 158,464,880 unique books (editions) in the world as of 2023.^[74]
codex (Q213924): ancient manuscript generally taking the form of the modern book: bound leaves of paper or parchment with information inscribed on both faces, attached at a center fold. Precursor of the modern book.	`Enwiki:` 173 `Commons:` 215 `Wikidata:` 576 `Estimate:` 2,000,000	According to available estimates, approximately 1–2 million codices (defined as handwritten bound books) were produced over the course of human history.^[27]
incunable (Q216665): genre of publication, book, pamphlet, or broadside that was printed before the year 1501 in Europe	`Enwiki:` 18 `Commons:` 52 `Wikidata:` 674 `Estimate:` 1,500,000	According to available sources, there are approximately 350,000 editions, around 1.5 million surviving copies, located in over 5,000 libraries worldwide.^[75]^[76] See also Incunabula Short Title Catalogue (29,777) and Universal Short Title Catalogue (350,000).
manuscript (Q87167): document written by hand or typed before the era of print, including literary, historical, religious, and scientific texts; distinguished from printed works by its unique, handcrafted nature.	`Enwiki:` 3,452 `Commons:` 2,875 `Wikidata:` 203,133 `Estimate:` 30,000,000	According to available estimates, approximately 10–30 million manuscripts (defined as individual handwritten documents) were produced over the course of human history.^[27]
discourse (Q190539): generalization of the notion of a conversation to any form of communication	`Enwiki:` 238 `Commons:` 70 `Wikidata:` 4,277 `Estimate:` 1,000,000	According to available estimates, approximately 1 million speeches have been delivered. See also Oral literature.
fictional entity (Q14897293): entity that only exists in a work of fiction	`Enwiki:` 36,703 `Commons:` 9,032 `Wikidata:` 157,919 `Estimate:` 1,000,000	According to available estimates, approximately 1 million fictional entities (characters, locations, events, objects, species, and universes) have been created across all forms of storytelling.^[27]
magazine (Q41298): publication that is typically distributed at a regular interval	`Enwiki:` 21,127 `Commons:` 4,785 `Wikidata:` 176,980 `Estimate:` 1,000,000	According to available estimates, approximately 1 million magazines have been published. According to available sources by country: China (9,000)^[77]
newspaper (Q11032): scheduled publication containing news of events, articles, features, editorials, and advertising; online, in print, or (usually) both	`Enwiki:` 11,609 `Commons:` 3,603 `Wikidata:` 60,693 `Estimate:` 500,000	According to available estimates, approximately 500,000 newspapers have been published. According to available sources by country: India (72,000)^[54] China (2,000)^[77]
poem (Q5185279): form of literature, work of poetry, often composed of verses	`Enwiki:` 1,689 `Commons:` 920 `Wikidata:` 16,256 `Estimate:` 10,000,000	According to available estimates, approximately 10 million poems have been published.^[27]
play (Q25379): theatrical dramatic work intended to be performed by actors (in theatre, radio or recorded for TV)	`Enwiki:` 267 `Commons:` 327 `Wikidata:` 8,835 `Estimate:` 1,000,000	According to available estimates, approximately 1 million plays have been published.^[27]
verse of a text (Q3556186): division of a text; especially used for sacred texts (Bible, Quran, etc.)	`Enwiki:` 550 `Commons:` 38 `Wikidata:` 4,092 `Estimate:` 1,000,000	According to available estimates, approximately 1 million verses from major universal works have been analysed individually.^[27] Number of verses by major universal work: Mahabharata (200,000) Iliad (15,693) The Divine Comedy (14,233) Odyssey (12,110) Aeneid (9,896) (For religious texts, see § Religion)
Total	`Enwiki:` 114,476 `Commons:` 35,359 `Wikidata:` 2,826,501 `Estimate:` 1,612,352,563

Performing arts

Performing arts are a form of art in which artists use their voices and/or their bodies, often in relation to other objects, to convey artistic expression. It is different from visual arts, which is when artists use paint or canvas or various materials to create physical or static art objects. Performing arts include several disciplines, each performed in front of a live audience.

Topic	Progress	Notes, sources and references
musical instrument (Q34379): device created or adapted to make musical sounds	`Enwiki:` 775 `Commons:` 3,083 `Wikidata:` 24,592 `Estimate:` 30,000	According to available estimates, there are approximately 30,000 musical instruments.^[27]
album (Q482994): grouping of album releases by an artist usually released at the same time with the same title and tracks but in different formats for consumption (digital, CD, LP)	`Enwiki:` 161,556 `Commons:` 263 `Wikidata:` 312,177 `Estimate:` 5,000,000	According to available sources, there are approximately 5 million albums.^[78] The Freedb database holds information for around 1.5 million compact discs (many are duplicates), AllMusic database contains entries for 800,000 unique albums, Discogs database contains over 890,000 master releases (several versions of releases) and nearly 6.5 million unique individual versions of releases,^[79] Jamendo project contains over 50,000 free and open albums. Record-Rama collection holds 3 million albums and singles. New albums in USA: 75,000 (2010), 96,100 (2009), 106,000 (2008), 76,000 (2006).^[80]
lyrics (Q602446): sequence of words that make up a song, usually consisting of verses and choruses	`Enwiki:` 55 `Commons:` 21 `Wikidata:` 45,849 `Estimate:` 0	According to available estimates, there are approximately 1 million lyrics.^[27]
song (Q7366): musical composition for voice(s)	`Enwiki:` 9,374 `Commons:` 1,047 `Wikidata:` 31,812 `Estimate:` 100,000,000	According to available estimates, there are approximately 100 million songs in the major streaming services, growing by about 100,000 new tracks per day.^[27]
music video (Q193977): video featuring a performance of a musical work	`Enwiki:` 0 `Commons:` 0 `Wikidata:` 0 `Estimate:` 5,000,000	According to available estimates, there are approximately 5 million music videos.^[27]
Total	`Enwiki:` 171,760 `Commons:` 4,414 `Wikidata:` 414,430 `Estimate:` 105,075,849

Visual arts

The visual arts are the art forms you perceive mainly through sight: painting, drawing, sculpture, photography, design, and similar disciplines.

Topic	Progress	Notes, sources and references
cave painting (Q214334): paintings found on cave walls and ceilings	`Enwiki:` 3 `Commons:` 22 `Wikidata:` 136 `Estimate:` 20,000,000	According to available sources, there are approximately 20 million cave paintings worldwide.^[81]
drawing (Q93184): visual artwork in two-dimensional medium	`Enwiki:` 310 `Commons:` 968 `Wikidata:` 177,638 `Estimate:` 100,000,000	According to available estimates, there are approximately 100 million drawings worldwide.^[27]
geoglyph (Q45791): motif produced on the ground; observed only remotely or from space	`Enwiki:` 42 `Commons:` 62 `Wikidata:` 107 `Estimate:` 1,000	According to available estimates, there are approximately 1,000 geoglyphs worldwide.^[27]
lithography (Q133036): printing technique	`Enwiki:` 2 `Commons:` 2 `Wikidata:` 213 `Estimate:` 10,000,000	According to available estimates, there are approximately 10 million lithographies worldwide.^[27]
mosaic (Q133067): image or writing made from an assemblage of small pieces of colored glass, stone, or other materials	`Enwiki:` 70 `Commons:` 777 `Wikidata:` 1,774 `Estimate:` 10,000,000	According to available estimates, there are approximately 10 million mosaics worldwide.^[27]
mural (Q219423): piece of artwork painted or applied directly on a large permanent surface	`Enwiki:` 350 `Commons:` 2,800 `Wikidata:` 10,571 `Estimate:` 5,000,000	According to available estimates, there are approximately 5 million murals worldwide.^[27]
painting (Q3305213): visual artwork, surface artistically covered with paint	`Enwiki:` 11,129 `Commons:` 30,020 `Wikidata:` 1,114,520 `Estimate:` 50,000,000	According to available estimates, there are approximately 50 million paintings worldwide.^[27] According to Art UK database, there are 213,000 artworks contained within the UK's national collection.^[82] See also Wikidata:WikiProject sum of all paintings.
petroglyph (Q42195): images carved on a rock surface as a form of rock art	`Enwiki:` 74 `Commons:` 229 `Wikidata:` 19,508 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million petroglyphs worldwide.^[27] According to available sources by petroglyph site: Valcamonica (300,000)^[83]
photograph (Q125191): image created by light falling on a light-sensitive surface	`Enwiki:` 259 `Commons:` 212 `Wikidata:` 91,360 `Estimate:` 4,000,000	According to available estimates, about 30–40 million photographs were created from 1826 to 1900, of which only about 5–10% survive today or roughly 1.5–4 million photographs.^[27]
sculpture (Q860861): three-dimensional work of art	`Enwiki:` 7,720 `Commons:` 55,873 `Wikidata:` 416,720 `Estimate:` 10,000,000	According to available estimates, there are approximately 10 million sculptures worldwide.^[27]
Total	`Enwiki:` 19,959 `Commons:` 90,965 `Wikidata:` 1,832,547 `Estimate:` 210,001,000

Geography

Geography is the study of the lands, features, inhabitants, and phenomena of planet Earth.

Human geography

Human geography, also known as anthropogeography, is a branch of geography that studies how people interact with places. It focuses on the spatial relationships between human communities, cultures, economies, people, lifestyles, and their environments.

Topic	Progress	Notes, sources and references
sovereign state (Q3624078): state that has the highest authority over a territory	`Enwiki:` 383 `Commons:` 252 `Wikidata:` 481 `Estimate:` 500	193 member states of the United Nations and historical states.^[84]
first-level administrative division (Q10864048): administrative division directly subordinate to or under administration of a national government	`Enwiki:` 5,021 `Commons:` 1,033 `Wikidata:` 6,633 `Estimate:` 5,000	According to available estimates, there are approximately 5,000 first‑level administrative divisions worldwide.^[27]
second-level administrative division (Q12357832): administrative division subordinate to or under administration of a first-level division	`Enwiki:` 48,354 `Commons:` 17,187 `Wikidata:` 69,304 `Estimate:` 20,000	According to available estimates, there are approximately 20,000 second‑level administrative divisions worldwide.^[27]
third-level administrative division (Q12357920): administrative division subordinate to or under administration of a second-level division	`Enwiki:` 95,951 `Commons:` 42,482 `Wikidata:` 223,315 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 third‑level administrative divisions worldwide.^[27]
fourth-level administrative division (Q14757767): administrative division subordinate to or under administration of a third-level division	`Enwiki:` 151,887 `Commons:` 67,231 `Wikidata:` 542,056 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million fourth‑level administrative divisions worldwide.^[27]
fifth-level administrative division (Q15640612): administrative division subordinate to or under administration of a fourth-level division	`Enwiki:` 3,703 `Commons:` 2,760 `Wikidata:` 712,067 `Estimate:` 5,000,000	According to available estimates, there are approximately 3–5 million fifth‑level administrative divisions worldwide.^[27]
sixth-level administrative division (Q22927291): administrative division subordinate to or under administration of a fifth-level division	`Enwiki:` 68 `Commons:` 39 `Wikidata:` 56,239 `Estimate:` 20,000,000	According to available estimates, there are approximately 10–20 million sixth‑level administrative divisions worldwide.^[27]
micronation (Q188443): small, unrecognized country	`Enwiki:` 105 `Commons:` 43 `Wikidata:` 167 `Estimate:` 500	According to available estimates, there are approximately 500 micronations.^[27]
neighborhood (Q123705): geographically localized community within a larger city, town or suburb	`Enwiki:` 29,821 `Commons:` 31,558 `Wikidata:` 225,962 `Estimate:` 10,000,000	According to available estimates, there are approximately 10 million neighborhoods.^[27]
Total	`Enwiki:` 335,293 `Commons:` 162,585 `Wikidata:` 1,836,224 `Estimate:` 36,126,000

Physical geography

Physical geography, also known as physiography, is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, hydrosphere, biosphere, and geosphere.

Topic	Progress	Notes, sources and references
continent (Q5107): large landmass identified by convention	`Enwiki:` 54 `Commons:` 27 `Wikidata:` 66 `Estimate:` 100	According to available estimates, there are approximately 100 continental entities recognized or proposed in geology (current continents and ancient or hypothesized ones).^[27]
canal (Q12284): man-made channel for water	`Enwiki:` 1,285 `Commons:` 3,297 `Wikidata:` 65,768 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 canals worldwide.^[27]
cave (Q35509): natural void under the Earth's surface	`Enwiki:` 1,844 `Commons:` 3,900 `Wikidata:` 21,606 `Estimate:` 563,000	According to available estimates, there are approximately 563,000 caves worldwide.^[27] According to available sources, there are 2,424 caves deeper than 300 m (total height) or longer than 3 km.^[85]
desert (Q8514): barren area of land where little precipitation occurs	`Enwiki:` 192 `Commons:` 124 `Wikidata:` 2,705 `Estimate:` 0	The total number of deserts is unknown.
oasis (Q43742): isolated area of vegetation in a desert	`Enwiki:` 62 `Commons:` 39 `Wikidata:` 201 `Estimate:` 2,000	According to available estimates, there are approximately 2,000 oasis worldwide.^[27]
forest (Q4421): trees populated area (>10%), larger than 5,000 m², and not used for agricultural or urban purposes	`Enwiki:` 1,967 `Commons:` 3,098 `Wikidata:` 30,611 `Estimate:` 40,000	According to available estimates, there are approximately 30,000–40,000 forests worldwide.^[27]
glacier (Q35666): large persistent body of ice	`Enwiki:` 3,174 `Commons:` 1,160 `Wikidata:` 9,792 `Estimate:` 400,000	According to available sources, there is satellite data for 198,000 glaciers, but including small glacierets would bring the total to over 400,000.^[86] According to available sources by country: Kyrgyzstan (8,000)^[87] United States (100,000)^[88]^[89]
hill (Q54050): landform that extends above the surrounding terrain in lower mountain ranges, smaller than a mountain	`Enwiki:` 4,135 `Commons:` 4,287 `Wikidata:` 331,332 `Estimate:` 30,000,000	According to available estimates, there are approximately 30 million hills worldwide.^[27]
island (Q23442): piece of sub-continental land completely surrounded by water	`Enwiki:` 14,432 `Commons:` 8,380 `Wikidata:` 213,802 `Estimate:` 900,000	According to available estimates, there are approximately 900,000 islands worldwide.^[27]
lake (Q23397): body of relatively still water, localized in a basin	`Enwiki:` 17,309 `Commons:` 18,683 `Wikidata:` 341,890 `Estimate:` 3,400,000	According to available sources, there are approximately 3.4 million lakes worldwide.^[90] According to available sources by country: Belarus (11,000)^[91] Canada (31,752)^[92]^[93] Finland (187,888)^[94] Norway (450,000) Sweden (150,000)^[95]
mountain (Q8502): large natural elevation of the Earth's surface	`Enwiki:` 29,945 `Commons:` 24,709 `Wikidata:` 516,355 `Estimate:` 300,000	According to available estimates, there are approximately 300,000 mountains higher than 1000 m worldwide.^[27]^[96] According to available sources by elevation: Above 8,000 m (14) 7,000 m (132) 6,000 m (1,500) 5,000 m (5,000) 4,000 m (10,000) 3,000 m (45,000) 2,000 m (100,000) 1,000 m (300,000)
mountain range (Q46831): geographic area containing several geologically related mountains	`Enwiki:` 4,959 `Commons:` 2,539 `Wikidata:` 29,480 `Estimate:` 0	The total number of mountain ranges is unknown.
river (Q4022): larger natural watercourse	`Enwiki:` 41,240 `Commons:` 22,181 `Wikidata:` 512,194 `Estimate:` 3,000,000	According to available estimates, there are approximately 3 million rivers worldwide.^[27]^[97] According to available sources, there are approximately 146,000+ in Africa^[98] and 104,000+ in Europe.^[99]. According to available sources by country: Azerbaijan (8,359)^[100] Brazil (25,000)^[101] China (20,000)^[102]^[103] El Salvador (300)^[104] Georgia (26,000)^[105] Guatemala (3,000)^[106] Kyrgyzstan (25,000)^[107]^[108] Nepal (6,000)^[109] Panama (500)^[110] Romania (4,000)^[111] Russia (120,000)^[112]^[113] Spain (1,800)^[114] Ukraine (71,000)^[115] United States (250,000)^[116]^[117] Venezuela (1,000)^[118]
sea (Q165): large body of saline water	`Enwiki:` 154 `Commons:` 53 `Wikidata:` 241 `Estimate:` 150	According to available sources, there are approximately 150 seas worldwide.^[27]
volcano (Q8072): natural, surface vent or fissure usually in a mountainous form	`Enwiki:` 1,297 `Commons:` 1,150 `Wikidata:` 3,191 `Estimate:` 1,500	According to available sources, there are approximately 1,500 volcanoes worldwide.^[119]
Total	`Enwiki:` 122,049 `Commons:` 93,627 `Wikidata:` 2,079,234 `Estimate:` 38,738,935

History

History is the systematic study of the past, focusing primarily on the human past. As an academic discipline, it analyses and interprets evidence to construct narratives about what happened and explain why it happened. Some theorists categorize history as a social science, while others see it as part of the humanities or consider it a hybrid discipline.

Calendars and events

A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single and specific day within such a system.

An event is any significant occurrence that happens at a specific time and place and produces consequences for people, systems, or the environment. Events may be planned or unplanned.

Topic	Progress	Notes, sources and references
calendar system (Q12132): system of organizing days for social, religious, commercial, or administrative purposes	`Enwiki:` 1,427 `Commons:` 271 `Wikidata:` 25,362 `Estimate:` 500	According to available sources, there are approximately 500 calendars.^[27]
calendar day of a given year (Q47150325): specific date (day) of a given year in Gregorian or Julian calendars. See property "point in time" (P585).	`Enwiki:` 5,845 `Commons:` 48,319 `Wikidata:` 201,212 `Estimate:` 730,000	Assuming 2,000 years, there are 730,000 calendar days.
planned event (Q1656682): temporary and scheduled happening, like a conference, festival, competition or similar	`Enwiki:` 492,545 `Commons:` 107,324 `Wikidata:` 1,965,682 `Estimate:` 1,300,000	According to available sources, there have been approximately 1.3 million events.^[120]
events in a specific year or time period (Q18340514): facts and events ranged in chronological order	`Enwiki:` 29,230 `Commons:` 1,078 `Wikidata:` 53,899 `Estimate:` 200,000	Assuming 200 countries and 1,000 years, there could be 200,000 articles. See also List of time periods, History by period, Category:Year lists.
disaster (Q3839081): hazard resulting in an event causing significant physical damage, destruction or death	`Enwiki:` 12,337 `Commons:` 3,708 `Wikidata:` 22,673 `Estimate:` 3,000,000	According to available estimates, there have been approximately 1–3 million disasters.^[27]
timeline (Q186117): display of a list of events in chronological order	`Enwiki:` 3,307 `Commons:` 124 `Wikidata:` 4,352 `Estimate:` 10,000	According to available estimates, approximately 10,000 timelines are needed to cover all major human developments.^[27]
Total	`Enwiki:` 544,691 `Commons:` 160,824 `Wikidata:` 2,273,180 `Estimate:` 5,240,500

GLAM

GLAM is an acronym for "galleries, libraries, archives, and museums", although other versions of the acronym exist, such as LAM, which incorporates only libraries, archives, and museums. More generally, GLAMs are publicly funded, publicly accountable institutions collecting cultural heritage materials. (For books and publications, see § Literature)

Topic	Progress	Notes, sources and references
archives (Q166118): agency or institution responsible for the preservation and communication of records selected for permanent preservation	`Enwiki:` 1,514 `Commons:` 2,305 `Wikidata:` 24,876 `Estimate:` 200,000	According to available estimates, there are approximately 200,000 archives worldwide.^[27] According to available sources by country: Spain (34,000)^[121] United Kingdom (2,389)^[122]
library (Q7075): institution charged with the care of a collection of literary, musical, artistic, or reference materials, such as books, manuscripts, recordings, or films	`Enwiki:` 4,580 `Commons:` 7,292 `Wikidata:` 112,692 `Estimate:` 2,600,000	According to OCLC, there are 72,000 libraries in 170 countries.^[123] According to available estimates, there are approximately 2.6 million libraries worldwide.^[27] According to available sources by country: Burundi (60)^[124] Canada (4,154)^[125] Croatia (232)^[126] Cuba (400)^[127] Czech Republic (6,245)^[128] Denmark (250)^[129] Finland (1,471)^[130]^[131] France (1,620)^[132]^[133] Germany (6,313)^[134] Greece (672)^[135] Hungary (3,518)^[136] Iceland (187)^[137] Latvia (998)^[138] Lithuania (1,478)^[139] Morocco (18)^[140] Netherlands (579)^[141] North Korea (200)^[142] Norway (1,108)^[143] Panama (40)^[144] Peru (200)^[145] Poland (9,230)^[146] Portugal (168)^[147] Romania (2,950)^[148] Russia (50,032)^[149] Sweden (324)^[150] Tanzania (16)^[151] Tunisia (200)^[152] Ukraine (21,857)^[153] United Kingdom (5,500)^[122] United States (139,000)^[154] Zimbabwe (76)^[155] According to available sources by size: British Library (150,000,000 items)^[156] Smithsonian Institution (137,000,000 items)^[157] Library of Congress (32,000,000 items)^[158] See also List of national and state libraries, List of the largest libraries in the United States, List of libraries in the ancient world, List of destroyed libraries and List of digital library projects.
museum (Q33506): institution that holds artifacts and other objects of scientific, artistic, cultural, historical, or other importance	`Enwiki:` 19,742 `Commons:` 35,529 `Wikidata:` 81,173 `Estimate:` 104,000	According to UNESCO, there are 104,000 museums worldwide.^[159] According to The World Museum Community, there are 55,000+ museums in 202 countries.^[160] About 17,673 museums in Europe, based on 2003 and 2008 figures.^[161] According to sources by country: Australia (1,019)^[162] Canada (2,400)^[163] Finland (280)^[131] France (1,000)^[132] Germany (4,000)^[164]^[134] Hungary (500)^[136] Iceland (50)^[137] Morocco (11)^[140] Pakistan (27)^[165] Peru (250)^[145] Poland (500)^[146] Portugal (300)^[147] Romania (400)^[148] Russia (1,000)^[149] Spain (1,400)^[166] Sweden (200)^[150] United Kingdom (2,500)^[122]^[167] United States (17,500)^[168] According to available sources by size: Metropolitan Museum of Art (2,000,000 items) Tokyo National Museum (110,000 items) Louvre Museum (30,000 items)^[169] See also List of national museums.
collection (Q2668072): set of purposely gathered physical or digital objects with some common characteristics	`Enwiki:` 21,508 `Commons:` 11,346 `Wikidata:` 719,714 `Estimate:` 3,000,000	According to available estimates, there are approximately 1–3 million collections in museums worldwide.^[27]
item of collection or exhibition (Q18593264): defines an item, such as an object or document, that is a member of a collection or part of a repository	`Enwiki:` 5,815 `Commons:` 14,120 `Wikidata:` 366,959 `Estimate:` 3,000,000,000	There is no global registry that aggregates collection sizes across all museum types (art, history, science, ethnography, archaeology, technology, etc.). According to available sources, there are approximately 1.1 billion specimens and objects in the collections of 73 of the world's largest natural history museums.^[170] Best supported estimate for all museums worldwide: 2–3 billion objects, based on extrapolation from the natural history domain and known collection sizes of major institutions.^[27]
Total	`Enwiki:` 53,159 `Commons:` 70,592 `Wikidata:` 1,305,414 `Estimate:` 3,005,904,000

Heraldry and vexillology

Heraldry is a discipline relating to the design, display, study and transmission of armorial bearings. A full heraldic achievement may include a coat of arms on a shield, helmet and crest, together with accompanying devices, such as supporters, badges, banners, and mottoes.

Vexillology is the study of the history, symbolism and usage of flags or, by extension, any interest in flags in general.

Topic	Progress	Notes, sources and references
coat of arms (Q14659): heraldic design on a shield, surcoat or tabard	`Enwiki:` 1,046 `Commons:` 2,797 `Wikidata:` 16,425 `Estimate:` 6,000,000	According to available sources, there are approximately 6 million coat of arms.^[171]
flag (Q14660): distinctive image used as a symbol, traditionally embodied as a piece of fabric	`Enwiki:` 1,475 `Commons:` 1,541 `Wikidata:` 12,511 `Estimate:` 90,000	According to available sources, there are approximately 90,000 flags.^[172]
Total	`Enwiki:` 2,521 `Commons:` 4,338 `Wikidata:` 28,936 `Estimate:` 6,090,000

Numismatics and philately

Numismatics is the study or collection of currency, including coins, tokens, paper money, medals, and related objects.

Philately is the study of postage stamps and postal history.

Topic	Progress	Notes, sources and references
banknote (Q47433): form of physical currency made of paper or polymer	`Enwiki:` 61 `Commons:` 49 `Wikidata:` 311 `Estimate:` 120,000	According to available estimates, there are approximately 120,000 banknotes.^[27]
coin (Q41207): piece of hard material produced in large quantities to facilitate trade	`Enwiki:` 239 `Commons:` 493 `Wikidata:` 76,418 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 coins.^[27]
medallion (Q131647): round piece of metal, often used as an award	`Enwiki:` 1,691 `Commons:` 1,297 `Wikidata:` 7,087 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million medals.^[27]
postage stamp (Q37930): small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage	`Enwiki:` 48 `Commons:` 68 `Wikidata:` 12,753 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 millon stamps, if we include errors, minor varieties, and local issues.^[27]
Total	`Enwiki:` 2,039 `Commons:` 1,907 `Wikidata:` 96,569 `Estimate:` 2,220,000

Politics

Politics is the activity of settling affairs in an organized society. Politics is usually concerned with resolving issues within a society via a government. Politicians are individuals engaged in the activity of politics. The branch of social science that studies politics and government is referred to as political science.

Topic	Progress	Notes, sources and references
opinion poll (Q49958): type of survey	`Enwiki:` 541 `Commons:` 25 `Wikidata:` 638 `Estimate:` 100,000	According to available estimates, approximately 100,000 opinion polls are needed to cover all major human developments.^[27]
public election (Q40231): process by which a population chooses the holder of a public office	`Enwiki:` 49,685 `Commons:` 4,301 `Wikidata:` 96,300 `Estimate:` 1,000,000	According to available estimates, there have been approximately 1 million elections in recorded history.^[27] By level of government, available estimates indicate the following scale of electoral activity worldwide: 6,000 national elections, 40,000–60,000 regional elections, 300,000–1,000,000 local elections, and 10,000 referendums.^[27]
referendum (Q43109): direct and universal vote in which an entire electorate is invited to vote on a particular proposal	`Enwiki:` 2,162 `Commons:` 392 `Wikidata:` 3,025 `Estimate:` 100,000	According to available estimates, there have been approximately 100,000 referendums in recorded history.^[27]
term of office (Q524572): time limit for a politician holding a given position (sometimes renewable)	`Enwiki:` 216 `Commons:` 112 `Wikidata:` 546 `Estimate:` 1,000,000	According to available estimates, there have been approximately 1 million terms of offices across all levels of government throughout recorded history.^[27]
Total	`Enwiki:` 52,604 `Commons:` 4,830 `Wikidata:` 100,509 `Estimate:` 2,200,000

Science

Science is a systematic discipline that builds and organises knowledge in the form of testable explanations about nature and society. It is driven by the scientific method: an empirical cycle that typically involves making observations, producing hypotheses, testing them with evidence, and drawing conclusions. Science encompasses this process and the body of knowledge it produces, which the scientific community continuously challenges, validates, and organises.

Astronomy

Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos.

Topic	Progress	Notes, sources and references
universe (Q1): totality consisting of space, time, matter and energy	`Enwiki:` 0 `Commons:` 0 `Wikidata:` 0 `Estimate:` 1	The universe is the totality of space, time, matter, and energy. The observable universe is the spherical region of the universe that contains all matter currently observable from Earth. The multiverse is a hypothetical group of multiple universes. The omniverse is the set or total number of supposedly co‑existing universes. The number of universes might be one (10⁰), according to standard cosmology, but other proposals suggest many universes (≈10¹⁰⁰) forming a multiverse with different physical laws. Even more speculative ideas go further: eternal‑inflation landscapes (≈10⁵⁰⁰) with vast numbers of possible universes, simulation hypotheses (up to 10ˣ simulated universes per higher‑level reality) where universes can be created artificially, modal realism (effectively 10^∞ possible worlds) where every possible world exists, and megaverse concepts (10^(10ˣ) multiverses) that group multiple multiverses. Finally, the mathematical universe hypothesis (10^(all mathematically possible structures)) claims that every mathematically possible reality is physically real.
void (Q845371): vast empty spaces between filaments which contain very few or no galaxies	`Enwiki:` 10 `Commons:` 1 `Wikidata:` 1,825 `Estimate:` 1,200	Observed galaxy surveys contain roughly 500–1,200 large voids in SDSS‑scale volumes. Cosmological simulations identify far more, over 1 billion voids in the GIGANTES suite.^[173]
galaxy filament (Q1133705): thread-like structures that form the boundaries between large voids in the universe	`Enwiki:` 17 `Commons:` 2 `Wikidata:` 18 `Estimate:` 37,000	SDSS maps about 37,000 galaxy filaments, the most authoritative observational count. Simulations contain vastly more, from hundreds of thousands to millions. Across the observable universe, the cosmic web likely contains millions of filaments, though only a fraction are currently mapped.^[27]
supercluster (Q27521): gravitationally-unbound collection of galaxy groups and clusters	`Enwiki:` 22 `Commons:` 4 `Wikidata:` 1,131 `Estimate:` 880	SDSS identifies about 880 galaxy superclusters. All‑sky surveys like 2MASS find roughly 500–600, depending on method. Simulations contain thousands, limited only by resolution and definition. Across the observable universe, the total is likely in the low thousands, though only a fraction are mapped.^[27]
galaxy cluster (Q204107): structure made up of a gravitationally-bound aggregation of hundreds of galaxies; is larger than a galaxy group	`Enwiki:` 125 `Commons:` 86 `Wikidata:` 84,447 `Estimate:` 26,000	SDSS identifies about 26,000 galaxy clusters, the largest optical catalog. Planck adds 1,653 SZ‑detected clusters, and X‑ray surveys add a few thousand more. Simulations predict around 100,000 clusters above the standard mass threshold. Across the observable universe, the total cluster population is on the order of one hundred thousand.^[27]
galaxy (Q318): large gravitationally bound system of stars and interstellar matter	`Enwiki:` 3,463 `Commons:` 4,937 `Wikidata:` 2,458,625 `Estimate:` 80,000,000	According to available estimates, the total number of galaxies in the observable universe ranges from 200,000,000,000 (2×10¹¹) to 2,000,000,000,000 (2×10¹²).^[174]^[175] Only about 80,000,000 galaxies have been described so far, in the REGALADE catalogue.^[176] The European Space Agency's Euclid telescope is expected to bring images of 1.5 billion galaxies over the next few years.^[177]
interstellar cloud (Q1054444): accumulation of gas, plasma and dust in a galaxy	`Enwiki:` 528 `Commons:` 434 `Wikidata:` 97,404 `Estimate:` 1,000,000	According to available estimates, the total number of interestellar clouds in the observable universe ranges from 10,000,000,000,000 (10¹³) to 100,000,000,000,000 (10¹⁴). Only a tiny fraction have been described, about 1 million interestellar clouds.^[27]
star (Q523): astronomical object consisting of a luminous spheroid of plasma held together by its own gravity	`Enwiki:` 5,491 `Commons:` 759 `Wikidata:` 4,569,562 `Estimate:` 1,811,709,771	According to available estimates, the total number of stars in the observable universe ranges from 10,000,000,000,000,000,000,000 (10²²) to 1,000,000,000,000,000,000,000,000 (10²⁴). Only a tiny fraction have been described, about 1,811,709,771 in the Gaia Data Release 3 by the Gaia European space mission.^[178]
black hole (Q589): astronomical object so massive, that anything falling into it, including light, cannot escape its gravity	`Enwiki:` 8 `Commons:` 4 `Wikidata:` 16 `Estimate:` 1,000,000	According to available estimates, the total number of black holes in the observable universe is 40,000,000,000,000,000,000 (4×10¹⁹).^[27] There are observational data for roughly 1 million supermassive black holes, mostly catalogued as AGN (Active Galactic Nucleus) in databases such as Milliquas, SDSS DR16Q, and the AllWISE AGN catalog.
pulsar (Q4360): highly magnetized, rapidly rotating neutron star or white dwarf	`Enwiki:` 72 `Commons:` 27 `Wikidata:` 2,807 `Estimate:` 2,000	According to available estimates, there are approximately 2,000 pulsars in our galaxy.^[27]
supernova (Q3937): star exploding at the end of its stellar lifespan	`Enwiki:` 114 `Commons:` 71 `Wikidata:` 14,620 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 supernovae in the observable universe.^[27]
exoplanet (Q44559): any planet beyond the Solar System	`Enwiki:` 1,601 `Commons:` 287 `Wikidata:` 10,073 `Estimate:` 6,300	According to available estimates, there are approximately 6,300 confirmed exoplanets. Thousands more candidates are awaiting confirmation from missions like TESS. The Milky Way likely contains hundreds of billions of planets overall.^[27]
natural satellite (Q2537): celestial body that orbits a planet or other smaller body in turn directly orbiting a star	`Enwiki:` 341 `Commons:` 178 `Wikidata:` 455 `Estimate:` 421	According to the NASA Jet Propulsion Laboratory list of solar system objects as of March 12, 2025, there were 421 known planetary satellites (including natural satellites of Earth and Pluto) in our solar system. ^[179]
asteroid (Q3863): minor planet of the inner Solar System; not a comet	`Enwiki:` 30,762 `Commons:` 2,167 `Wikidata:` 249,732 `Estimate:` 1,441,778	According to the NASA Jet Propulsion Laboratory list of solar system objects as of March 12, 2025, there were 1,441,778 known asteroids in our solar system. Of these, 773,916 were numbered. ^[179]
comet (Q3559): icy small astronomical object	`Enwiki:` 788 `Commons:` 168 `Wikidata:` 1,403 `Estimate:` 4,001	According to the NASA Jet Propulsion Laboratory list of solar system objects as of March 12, 2025, there were 4,001 known comets in our solar system. Of these, 589 were numbered. ^[179]
Total	`Enwiki:` 43,342 `Commons:` 9,125 `Wikidata:` 7,492,118 `Estimate:` 1,895,239,352

Biology

Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, origin, evolution, and distribution of life. (For fossils and specimens, see § Items of collections)

Topic	Progress	Notes, sources and references
domain (Q146481): taxonomic rank (for "ordinary" organisms thus not viruses)	`Enwiki:` 4 `Commons:` 2 `Wikidata:` 7 `Estimate:` 0	According to the domain system, the tree of life consists of either three domains, Archaea, Bacteria, and Eukarya, or two domains, Archaea and Bacteria, with Eukarya included in Archaea. In the three-domain model, the first two are prokaryotes, single-celled microorganisms without a membrane-bound nucleus. All organisms that have a cell nucleus and other membrane-bound organelles are included in Eukarya and called eukaryotes. Non-cellular life, most notably the viruses, is not included in this system.
kingdom (Q36732): taxonomic rank	`Enwiki:` 23 `Commons:` 5 `Wikidata:` 41 `Estimate:` 0	Traditionally, textbooks from the United States and some of Canada have used a system of six kingdoms (Animalia, Plantae, Fungi, Protista, Archaea or Archaebacteria, and Bacteria or Eubacteria), while textbooks in other parts of the world have used five kingdoms (Animalia, Plantae, Fungi, Protista and Monera).
phylum (Q38348): main taxonomic rank (under the rank kingdom)	`Enwiki:` 210 `Commons:` 28 `Wikidata:` 365 `Estimate:` 0	Depending on definitions, the animal kingdom Animalia contains about 32 phyla, the plant kingdom Plantae contains about 14 phyla, and the fungus kingdom Fungi contains about eight phyla.
class (Q37517): taxonomic rank in biology	`Enwiki:` 522 `Commons:` 90 `Wikidata:` 1,142 `Estimate:` 1,500	According to available estimates, there are approximately 1,500 biological classes in nature.^[27]
order (Q36602): taxonomic rank	`Enwiki:` 1,956 `Commons:` 389 `Wikidata:` 3,898 `Estimate:` 500	According to available estimates, there are approximately 500 biological orders in nature.^[27]
family (Q35409): taxonomic rank (or a taxon at that rank) between order and genus	`Enwiki:` 10,849 `Commons:` 2,117 `Wikidata:` 22,751 `Estimate:` 3,500	According to available estimates, there are approximately 3,500 biological families in nature.^[27]
genus (Q34740): taxonomic rank used in the biological classification of living and fossil organisms, and viruses	`Enwiki:` 109,337 `Commons:` 21,509 `Wikidata:` 281,735 `Estimate:` 200,000	According to available estimates, there are approximately 200,000 biological genera in nature.^[27]
species (Q7432): one of the basic units of biological classification and a taxonomic rank	`Enwiki:` 384,658 `Commons:` 248,572 `Wikidata:` 3,262,899 `Estimate:` 8,700,000	According to available sources, there are approximately 8.7 million living species on Earth, not including extinct ones.^[180] More than 99% of all species, amounting to over 5 billion species,^[181] that ever lived on Earth are extinct.^[182]^[183]^[184]
cell line (Q21014462): population of cells that originates from a primary culture, adapted to grow and divide under laboratory conditions	`Enwiki:` 95 `Commons:` 39 `Wikidata:` 153,642 `Estimate:` 0	The total number of cell lines is unknown.
gene (Q7187): basic physical and functional unit of heredity	`Enwiki:` 12,276 `Commons:` 1,676 `Wikidata:` 1,273,118 `Estimate:` 300,000,000	According to available estimates, the approximately 8.7 million eukaryotic species on Earth collectively contain an estimated 200–300 million unique genes.^[27]
protein (Q8054): biomolecule or biomolecule complex largely consisting of chains of amino acid residues	`Enwiki:` 2,085 `Commons:` 608 `Wikidata:` 1,034,740 `Estimate:` 149,810,139	According to available sources, there are approximately 149 million known proteins across all life forms.^[185]
non-coding RNA (Q427087): class of RNA that is not translated into proteins	`Enwiki:` 281 `Commons:` 4 `Wikidata:` 116,028 `Estimate:` 280,000	According to available sources, there are approximately 280,000 human non-coding RNA genes, identified algorithmically from 690,000 transcripts.^[186]
Total	`Enwiki:` 522,296 `Commons:` 275,039 `Wikidata:` 6,150,366 `Estimate:` 459,149,694

Chemistry and physics

Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies matter: composition, structure, properties, behavior and the changes they undergo during reactions with other substances.

Physics is the scientific study of matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force.

Topic	Progress	Notes, sources and references
chemical compound (Q11173): pure chemical substance consisting of two or more different chemical elements	`Enwiki:` 336 `Commons:` 150 `Wikidata:` 142,691 `Estimate:` 290,000,000	According to available sources, there are approximately 290 million chemical compounds.^[187]^[188] This number grows rapidly, about 15,000 new substances per day, driven largely by organic chemistry and new materials research.^[189]
chemical reaction (Q36534): process that results in the interconversion of chemical species	`Enwiki:` 1,879 `Commons:` 1,297 `Wikidata:` 3,670 `Estimate:` 150,000,000	According to available sources, there are approximately 150 million single and multi-step chemical reactions.^[190]
crystal structure (Q895901): unique arrangement of atoms or molecules in a crystalline liquid or solid	`Enwiki:` 31 `Commons:` 305 `Wikidata:` 3,261 `Estimate:` 1,400,000	According to available sources, there are approximately 1.4 million crystal structures.^[191] This number grows about 60,000 new crystal structures per year.
subatomic particle (Q177013): particle smaller than an atom	`Enwiki:` 7 `Commons:` 1 `Wikidata:` 9 `Estimate:` 500	According to available sources, there are approximately 500 subatomic particles.^[192]
Total	`Enwiki:` 2,253 `Commons:` 1,753 `Wikidata:` 149,631 `Estimate:` 441,400,500

Mathematics

Mathematics is a field of knowledge concerned with abstract concepts such as numbers, geometric shapes, sets, functions, and probabilities. It uses logical reasoning and proof to study and establish their properties, often expressed as theorems, formulas, and equations. Mathematics is used to model and solve problems in science, engineering, technology, economics, and everyday life.

Topic	Progress	Notes, sources and references
algorithm (Q8366): sequence of instructions to perform a task	`Enwiki:` 1,643 `Commons:` 211 `Wikidata:` 2,456 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 algorithms.^[27]
number (Q11563): mathematical object used to count, label, and measure	`Enwiki:` 3,145 `Commons:` 26,379 `Wikidata:` 416,712 `Estimate:` 1,000,000	According to mathematics, there are ℵ₀ (infinite) numbers, integers and reals. Let's assume 1 million notable numbers.
prime number (Q49008): positive integer with exactly two divisors, 1 and itself	`Enwiki:` 487 `Commons:` 1,614 `Wikidata:` 137,664 `Estimate:` 1,000,000	According to mathematics, there are ℵ₀ (infinite) prime numbers. Let's assume 1 million notable prime numbers.
integer sequence (Q2297602): ordered succession of integers, defined by a formula, recurrence, or property of its members	`Enwiki:` 139 `Commons:` 18 `Wikidata:` 223 `Estimate:` 400,000	According to available sources, there are approximately 400,000 integer sequences.^[193]
Total	`Enwiki:` 5,414 `Commons:` 28,222 `Wikidata:` 557,055 `Estimate:` 2,410,000

Medicine

Medicine is the science and practice of caring for patients, managing the diagnosis, prognosis, prevention, treatment and palliation of their injury or disease, while promoting their health.

Topic	Progress	Notes, sources and references
clinical trial (Q30612): human subject research in medicine	`Enwiki:` 37 `Commons:` 6 `Wikidata:` 391,684 `Estimate:` 589,453	According to available sources, there are approximately 589,453 clinical trials.^[194]
disease (Q12136): abnormal biological process in an organism driven by a specific pathophysiological mechanism	`Enwiki:` 2,808 `Commons:` 727 `Wikidata:` 6,781 `Estimate:` 55,000	According to available sources, there are approximately 12,000 diseases.^[195] According to available estimates, there are approximately 40,000 diseases, and over 55,000 codes in ICD-11.^[27] See also Category:Animal diseases and Lists of plant diseases.
drug (Q8386): chemical substance having an effect on the body	`Enwiki:` 1,213 `Commons:` 271 `Wikidata:` 2,473 `Estimate:` 21,000	According to available sources, there are approximately 21,000 drugs.^[196]
medical procedure (Q796194): process of medicine done to heal; course of action intended to achieve a result in the delivery of healthcare	`Enwiki:` 1,334 `Commons:` 365 `Wikidata:` 394,415 `Estimate:` 78,000	According to available estimates, there are approximately 78,000 medical procedures.^[27]
psychology (Q9418): study of mental functions and behaviours	`Enwiki:` 127 `Commons:` 52 `Wikidata:` 291 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 psychology topics.^[27]
psychiatry (Q7867): branch of medicine devoted to the study, diagnosis, treatment, and prevention of mental disorders	`Enwiki:` 18 `Commons:` 3 `Wikidata:` 34 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 psychiatry topics.^[27]
Total	`Enwiki:` 5,537 `Commons:` 1,424 `Wikidata:` 795,678 `Estimate:` 763,453

Research

Research is creative and systematic work undertaken to increase the stock of knowledge. It involves the collection, organization, and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness to controlling sources of bias and error.

Topic	Progress	Notes, sources and references
university laboratory (Q120335186): type of educational facility	`Enwiki:` 0 `Commons:` 1 `Wikidata:` 2 `Estimate:` 3,000,000	According to available estimates, there are approximately 1–3 million academic labs.^[27]
data set (Q1172284): collection of data, publication type	`Enwiki:` 14,820 `Commons:` 3,055 `Wikidata:` 103,155 `Estimate:` 5,000,000	According to available estimates, there are approximately 1–5 million datasets.^[27]
research group (Q1241025): group of researchers often from the same faculty, specialized on the same subject, working together on the issue or topic	`Enwiki:` 98 `Commons:` 32 `Wikidata:` 5,620 `Estimate:` 200,000	According to available estimates, there are approximately 100,000–200,000 research groups.^[27]
science project (Q1298668): project of one or more scientists, or of an organization in a scientific field	`Enwiki:` 1,833 `Commons:` 595 `Wikidata:` 485,138 `Estimate:` 10,000,000	According to available estimates, there are approximately 3–10 million active research projects.^[27]
Total	`Enwiki:` 16,751 `Commons:` 3,683 `Wikidata:` 593,915 `Estimate:` 18,200,000

Society

A society is a group of people related to each other through persistent relations, or a large social grouping sharing the same geographical or virtual territory, subject to the same political authority and dominant cultural expectations.

Biography

A biography is a detailed description or account of a person's life. It involves more than just basic facts like education, work, relationships, and death; it portrays a person's experience of these life events.

Topic	Progress	Notes, sources and references
human (Q5): any single member of Homo sapiens, unique extant species of the genus Homo	`Enwiki:` 2,870,586 `Commons:` 1,000,000 `Wikidata:` 11,297,772 `Estimate:` 108,000,000	As of March 2017, Wikidata listed 2,653,023 male biographies and 530,490 female biographies,^[197] a gender ratio of roughly 5:1. As of 2026, the English Wikipedia contains 2,870,586 biographies. If we assume that a typical city of 100,000 inhabitants produces around 100 notable individuals (artists, scientists, writers, politicians, athletes, and many more), this implies a 1:1000 notability rate. Applying that ratio to the current world population of about 8 billion yields an estimated 8 million notable living people. With roughly 360,000 births per day, this model suggests that about 360 future notable individuals are born each day.^[198] Looking to the past, approximately 100 billion humans have ever lived.^[199] Using the same 1:1000 ratio gives a rough estimate of 100 million historically notable people, plus the 8 million living ones. Of course, only a tiny fraction of ancient or pre‑modern individuals are documented, so the number of recoverable biographies is far smaller. Still, a broad estimate would place the total number of notable biographies in human history at over 108 million. Lists of people by occupation (cat) and nationality are desirable too. According to Wikidata, there are over 9,115 occupations (6,841 with English labels).^[200] See also Category:Obsolete occupations.
given name (Q202444): name typically used to differentiate people from the same family, clan, or other social group who have a common last name	`Enwiki:` 16,209 `Commons:` 28,048 `Wikidata:` 132,337 `Estimate:` 27,000,000	According to available sources, there are approximately 27 million given names or forenames.^[201]
family name (Q101352): part of a naming scheme for individuals, used in many cultures worldwide	`Enwiki:` 75,741 `Commons:` 202,564 `Wikidata:` 714,200 `Estimate:` 27,000,000	According to available sources, there are approximately 27 million family names or surnames.^[201]
title (Q216353): qualified name, rank, or other indication of a class or role given to or inherited by a person, often affixed to a person's name	`Enwiki:` 7,375 `Commons:` 1,957 `Wikidata:` 23,696 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million titles.^[27]
award (Q618779): something given to a person or a group of people to recognize their merit or excellence	`Enwiki:` 24,337 `Commons:` 7,634 `Wikidata:` 89,361 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million awards.^[27]
Total	`Enwiki:` 2,994,248 `Commons:` 1,240,203 `Wikidata:` 12,257,366 `Estimate:` 164,000,000

Gastronomy

Gastronomy is the study of the relationship between food and culture, the art of preparing and serving rich or delicate and appetizing food, the cooking styles of particular regions, and the science of good eating.

Topic	Progress	Notes, sources and references
cuisine (Q1778821): characteristic style of cooking practices and traditions	`Enwiki:` 610 `Commons:` 162 `Wikidata:` 1,204 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million cuisine topics.^[27]
food (Q2095): any substance consumed to provide nutritional support for the body; form of energy stored in chemical	`Enwiki:` 3,797 `Commons:` 3,890 `Wikidata:` 19,495 `Estimate:` 3,000,000	According to available estimates, there are approximately 3 million foods.^[27]
recipe (Q219239): a set of instructions for preparing a processed food item	`Enwiki:` 21 `Commons:` 31 `Wikidata:` 3,412 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million recipes.^[27]
drink (Q40050): kind of liquid which is specifically prepared for human consumption	`Enwiki:` 1,510 `Commons:` 1,166 `Wikidata:` 26,729 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million drinks.^[27]
Total	`Enwiki:` 5,938 `Commons:` 5,249 `Wikidata:` 50,840 `Estimate:` 6,000,000

Language

Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed forms, and may also be conveyed through writing. Human language is characterized by its cultural and historical diversity, with significant variations observed between cultures and across time.

Topic	Progress	Notes, sources and references
human language (Q20162172): set of all languages currently or formerly spoken, written, or signed by humans (excluding computer languages and mathematical/logically-formal languages)	`Enwiki:` 7,495 `Commons:` 114 `Wikidata:` 9,419 `Estimate:` 7,500	According to available estimates, there are approximately 6,900 living languages, around 600 documented extinct ones, and tens of thousands more that disappeared throughout human history, possibly over 100,000 in total.^[27] Rosetta Project is a permanent archive of 1,500 languages (13,000 microscopic pages of text) in a contemporary version of the historic Rosetta Stone to last from 2000 to 12,000 AD. See also List of constructed languages, Lists of extinct languages and List of constructed languages. And wiktionary:Category:All languages for words in all languages.
writing system (Q8192): any conventional method of visually representing verbal or signed communication	`Enwiki:` 1,434 `Commons:` 1,722 `Wikidata:` 3,267 `Estimate:` 10,000	According to available estimates, there are approximately 300 living writing systems, several dozen documented extinct scripts, and possibly over 10,000 in total that vanished across human history.^[27]
Unicode character (Q29654788): character in the Unicode standard	`Enwiki:` 1,221 `Commons:` 12,145 `Wikidata:` 168,435 `Estimate:` 297,334	As of Unicode version 17.0, there are 297,334 assigned characters with code points, covering 172 modern and historical scripts, as well as multiple symbol sets.^[202]
Total	`Enwiki:` 10,150 `Commons:` 13,981 `Wikidata:` 181,121 `Estimate:` 314,834

Organization

An organization is an entity comprising one or more people and having a particular purpose.

Topic	Progress	Notes, sources and references
civilization (Q8432): organized cultural society that encounters many communities, on a scale of a nation or human, as well as a system of development	`Enwiki:` 78 `Commons:` 24 `Wikidata:` 108 `Estimate:` 200	According to available estimates, there have been approximately 200 civilizations throughout human history.^[27]
business (Q4830453): organization undertaking commercial, industrial, or professional activity	`Enwiki:` 126,587 `Commons:` 112,352 `Wikidata:` 772,016 `Estimate:` 359,000,000	According to available sources, there are approximately 359 million companies worldwide.^[203]
craft (Q2207288): field of work that requires particular skills and knowledge of skilled work	`Enwiki:` 208 `Commons:` 393 `Wikidata:` 1,628 `Estimate:` 3,000	According to available estimates, there are approximately 3,000 crafts.^[27]
economics (Q8134): social science that studies the production, distribution, and consumption of goods and services	`Enwiki:` 51 `Commons:` 12 `Wikidata:` 159 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 economics topics.^[27]
hobby (Q47728): regular leisure activity that is done usually for enjoyment	`Enwiki:` 6,126 `Commons:` 1,138 `Wikidata:` 12,922 `Estimate:` 20,000	According to available estimates, there are approximately 20,000 hobbies.^[27]
law (Q7748): system of rules and guidelines, generally backed by governmental authority	`Enwiki:` 3,585 `Commons:` 668 `Wikidata:` 39,340 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 law topics.^[27]
legal case (Q2334719): dispute resolved by a court	`Enwiki:` 11,660 `Commons:` 317 `Wikidata:` 44,500 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million legal cases.^[27]
organization (Q43229): social entity established to meet needs or pursue goals	`Enwiki:` 0 `Commons:` 178,851 `Wikidata:` 7,268,346 `Estimate:` 200,000,000	According to available estimates, there are approximately 200 million organizations worldwide (assuming 200 countries and an average of 1,000,000 organizations by country). According to available sources, non-governmental organizations by country: India (3,300,000)^[204]^[205] Russia (277,000)^[206] United States (1,500,000)^[207]
position (Q4164871): social role with a set of powers and responsibilities within an organization	`Enwiki:` 24,896 `Commons:` 7,865 `Wikidata:` 243,327 `Estimate:` 10,000,000	According to available estimates, there have been approximately 10 million positions throughout human history.^[27]
Total	`Enwiki:` 173,191 `Commons:` 301,620 `Wikidata:` 8,382,346 `Estimate:` 570,133,200

Philosophy

Philosophy is a systematic study of general and fundamental questions concerning topics like existence, knowledge, mind, reason, language, and value.

Topic	Progress	Notes, sources and references	Image
philosophy (Q5891): study of the truths and principles of being, schools of thought, knowledge, or conduct	`Enwiki:` 10,575 `Commons:` 2,445 `Wikidata:` 65,127 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 philosophy topics.^[27]
Total	`Enwiki:` 10,575 `Commons:` 2,445 `Wikidata:` 65,127 `Estimate:` 100,000

Religion, mythology and folkore

Religion is a range of social-cultural systems, including designated behaviors and practices, ethics, morals, beliefs, worldviews, texts, sanctified places, prophecies, or organizations, that generally relate humanity to supernatural, transcendental, and spiritual elements.

Mythology is the collection of stories, symbols, and supernatural narratives a culture uses to explain the world: its origins, its gods, its values, and the forces that shape life.

Folklore is the body of expressive culture shared by a particular group of people, culture or subculture. This includes oral traditions such as tales, legends, proverbs, poems, and jokes.

Topic	Progress	Notes, sources and references
religion (Q9174): social-cultural system	`Enwiki:` 750 `Commons:` 260 `Wikidata:` 1,365 `Estimate:` 4,200	According to available sources, there are approximately 4,200 religions.^[208]
religious concept (Q23847174): abstract object associated with religion	`Enwiki:` 1,157 `Commons:` 1,030 `Wikidata:` 4,999 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 religious concepts.^[27] pl:Encyklopedia Katolicka has over 40,000 definitions (it includes things like Fire in religion).
verse of the Bible (Q29154550): individual verse within a book of the Bible	`Enwiki:` 529 `Commons:` 26 `Wikidata:` 4,012 `Estimate:` 50,938	According to available estimates, the Bible contains 31,102 verses, the Qur’an has 6,236 verses, the Bhagavad Gita includes 700, the Dhammapada has 423, the Guru Granth Sahib features roughly 5,894 hymns, the Tao Te Ching consists of 81 chapters, and the Book of Mormon includes roughly 6,604 verses.^[27]
culture by ethnic group (Q120870093): Wikidata metaclass	`Enwiki:` 57 `Commons:` 10 `Wikidata:` 147 `Estimate:` 10,000	According to available estimates, there have been approximately 10,000 cultures throughout human history.^[27]
folklore by ethnic group (Q24890109): Wikidata metaclass	`Enwiki:` 26 `Commons:` 1 `Wikidata:` 46 `Estimate:` 10,000	According to available estimates, there have been approximately 10,000 folklores throughout human history.^[27]
mythology by ethnic group (Q19718870): Wikidata metaclass	`Enwiki:` 90 `Commons:` 2 `Wikidata:` 155 `Estimate:` 10,000	According to available estimates, there have been approximately 10,000 mythologies throughout human history.^[27]
pseudoscience (Q483677): unscientific claims wrongly presented as scientific	`Enwiki:` 293 `Commons:` 90 `Wikidata:` 611 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 pseudoscience topics.^[27]
Total	`Enwiki:` 2,902 `Commons:` 1,419 `Wikidata:` 11,335 `Estimate:` 285,138

Sports

A sport is a physical activity or game, often competitive and organized, that maintains or improves physical ability and skills. Sport may provide enjoyment to participants and entertainment to spectators. The number of participants in a particular sport can vary from hundreds of people to a single individual.

Topic	Progress	Notes, sources and references
sport (Q349): form of event or activity involving competition; series of activities that provides challenges for an individual or team/s of participants	`Enwiki:` 7,401 `Commons:` 2,908 `Wikidata:` 33,220 `Estimate:` 10,000	According to available estimates, there are approximately 10,000 sports.^[27]
sports season (Q27020041): season of a sports league or competition, generally a specific one year period	`Enwiki:` 193,741 `Commons:` 14,984 `Wikidata:` 346,502 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million sports seasons.^[27]
sports match (Q118496986): instance of competition of sports	`Enwiki:` 9,618 `Commons:` 16,962 `Wikidata:` 165,640 `Estimate:` 10,000,000	According to available estimates, there are approximately 10 million sports matches.^[27]
Total	`Enwiki:` 210,760 `Commons:` 34,854 `Wikidata:` 545,362 `Estimate:` 11,010,000

Technology

Technology is the making, modification, usage, and knowledge of physical tool, machine, techniques, craft, system, methods of organization, in order to solve a problem, improve a preexisting solution to a problem, achieve a goal or perform a specific function. It can also refer to the collection of such tools, machinery, modifications, arrangements and procedures. Technologies significantly affect human as well as other animal species' ability to control and adapt to their natural environments. (See also: Category:Technology-related lists).

Computing

Computing is the study and experimentation of algorithmic processes, and the development of both hardware and software.

Topic	Progress	Notes, sources and references
artificial intelligence (Q11660): field that develops and studies software enabling machines to exhibit intelligent behavior	`Enwiki:` 81 `Commons:` 40 `Wikidata:` 244 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 artificial intelligence topics.^[27]
computer hardware (Q3966): physical components of a computer	`Enwiki:` 831 `Commons:` 389 `Wikidata:` 1,869 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 computer hardware components.^[27]
file format (Q235557): formalized structure of information stored in a storage medium	`Enwiki:` 7,947 `Commons:` 663 `Wikidata:` 85,070 `Estimate:` 50,000	According to available estimates, there are approximately 50,000 file formats.^[27]^[209]^[210]
malware (Q14001): software that is intentionally hostile, intrusive, or damaging to a computer or network	`Enwiki:` 218 `Commons:` 14 `Wikidata:` 324 `Estimate:` 20,000	According to available sources, there are approximately 20,000 notable computer viruses.^[211]
software (Q7397): non-tangible executable component of a computer	`Enwiki:` 0 `Commons:` 0 `Wikidata:` 10,420,241 `Estimate:` 500,000	According to available estimates, there are approximately 500,000 notable applications. According to repositories: App Store (550,000)^[212] Google Play (500,000)^[213] Ubuntu Software Center (30,000)
website (Q35127): set of related web pages served from a single web domain	`Enwiki:` 10,046 `Commons:` 3,401 `Wikidata:` 47,012 `Estimate:` 200,000	According to available estimates, there are approximately 200,000 notable websites.^[27]
Total	`Enwiki:` 19,123 `Commons:` 4,507 `Wikidata:` 10,554,760 `Estimate:` 970,000

Engineering

Engineering is the practice of systematically applying natural science and mathematics to design and improve systems, devices, or processes that solve problems under constraints.

Topic	Progress	Notes, sources and references
engineering (Q11023): type of applied science	`Enwiki:` 461 `Commons:` 217 `Wikidata:` 1,384 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million engineering topics.^[27]
patent (Q253623): monopoly granted on a new invention; publication type	`Enwiki:` 9 `Commons:` 54 `Wikidata:` 316,763 `Estimate:` 140,000,000	According to available estimates, total patents ever granted worldwide likely exceed 100 million.^[27] According to patents databases: Espacenet (140,000,000) United States Patent and Trademark Office (7,950,000)
technical standard (Q317623): required norm or standard established to make it easier to do something in a consistent way	`Enwiki:` 11,997 `Commons:` 1,567 `Wikidata:` 114,750 `Estimate:` 25,000	According to available estimates, there are approximately 25,000 international standards and standards‑type documents.^[27]
trademark (Q167270): trade identifier of products or services	`Enwiki:` 8,166 `Commons:` 2,925 `Wikidata:` 22,854 `Estimate:` 50,000,000	According to available estimates, there are approximately 50 million trademarks worldwide. Over 15 million filings happen each year. The USPTO alone has 3 million active trademarks.^[27]
Total	`Enwiki:` 20,633 `Commons:` 4,763 `Wikidata:` 455,751 `Estimate:` 191,025,000

Transport

Transport is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipelines, and space. The field can be divided into infrastructure, vehicles, and operations. Transport enables human trade, which is essential for the development of civilizations.

Topic	Progress	Notes, sources and references
airport (Q1248784): location where aircraft take off and land with extended support facilities, mostly for commercial air transport	`Enwiki:` 12,590 `Commons:` 4,436 `Wikidata:` 25,061 `Estimate:` 84,330	According to available sources, there are approximately 84,330 airports worldwide.^[214]^[215]^[216]
bus station (Q494829): structure, larger than a bus stop, where city or intercity buses stop to pick up and drop off passengers	`Enwiki:` 1,133 `Commons:` 2,064 `Wikidata:` 4,000 `Estimate:` 50,000	According to available estimates, there are approximately 50,000 bus stations worldwide.^[27]
heliport (Q502074): airport designed for helicopter use	`Enwiki:` 202 `Commons:` 84 `Wikidata:` 6,669 `Estimate:` 25,000	According to available estimates, there are approximately 25,000 heliports worldwide.^[27]
means of transport (Q106839123): specific physical object, vehicle, or agent used to carry and move people or goods from one location to another	`Enwiki:` 52,152 `Commons:` 73,435 `Wikidata:` 227,203 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million means of transport.^[27]
parking area (Q6501349): cleared area that is intended for parking vehicles	`Enwiki:` 818 `Commons:` 2,152 `Wikidata:` 4,046 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million parkings worldwide.^[27]
port (Q44782): maritime facility where ships may dock to load and discharge passengers and cargo	`Enwiki:` 1,547 `Commons:` 3,117 `Wikidata:` 11,112 `Estimate:` 20,000	According to available sources, there are approximately 20,000 ports worldwide.^[217]^[218]
railway line (Q728937): constructional unit in rail transport, the route or way of rail tracks between defined locations	`Enwiki:` 10,641 `Commons:` 10,676 `Wikidata:` 29,429 `Estimate:` 1,000,000	According to available estimates, there are approximately 1 million railway lines worldwide.^[27]
railway station (Q55488): railway facility where trains regularly stop to load or unload passengers and/or freight	`Enwiki:` 57,116 `Commons:` 73,981 `Wikidata:` 141,360 `Estimate:` 200,000	According to available estimates, there are approximately 200,000 train stations worldwide.^[27]
road (Q34442): wide way leading from one place to another, especially one with a specially prepared surface which vehicles can use	`Enwiki:` 35,836 `Commons:` 244,432 `Wikidata:` 884,895 `Estimate:` 36,000,000	According to available sources, there are approximately 36 million roads worldwide.^[219]^[220]
traffic sign (Q170285): signboard displaying information for road users	`Enwiki:` 48 `Commons:` 1,508 `Wikidata:` 12,891 `Estimate:` 100,000	According to available estimates, there are approximately 100,000 traffic signs.^[27]
Total	`Enwiki:` 172,083 `Commons:` 415,885 `Wikidata:` 1,346,666 `Estimate:` 39,479,330

Special pages

Pages are placed in different namespaces according to their contents. Encyclopedic pages (articles, lists and disambiguations) are located in namespace 0 (main), files are in the namespace 6, and categories are in namespace 14. All namespaces have an associated talk page namespace and all of them allow redirects.

Page type	Progress	Notes, sources and references
Wikimedia category (Q4167836): use with 'instance of' (P31) for Wikimedia category	`Enwiki:` 2,643,017 `Commons:` 3,497,206 `Wikidata:` 5,976,441 `Estimate:` 0	According to database reports, the English Wikipedia contains approximately 2.6 million categories, while Wikimedia Commons includes about 3.4 million categories.^[221]^[222]
Wikimedia disambiguation page (Q4167410): type of wiki page usually in main namespace (article namespace, ns=0) containing links to articles with similar names, and very little details only, use with P31 "instance of"	`Enwiki:` 419,051 `Commons:` 18,871 `Wikidata:` 1,630,546 `Estimate:` 0	According to database reports, the English Wikipedia contains approximately 400,000 disambiguation pages.^[223]
Wikimedia list article (Q13406463): page of a Wikimedia project with a list of something	`Enwiki:` 243,559 `Commons:` 30,395 `Wikidata:` 555,163 `Estimate:` 0	According to database reports, the English Wikipedia contains approximately 250,000 lists (including outlines and timelines).^[221]^[222]
Wikimedia portal (Q4663903): pages on a Wikimedia wiki intended to serve as "Main Pages" for specific areas of knowledge or information, or for specific audiences and activities. Use with P31 'instance of' for them	`Enwiki:` 757 `Commons:` 10 `Wikidata:` 6,037 `Estimate:` 10,000	According to available sources, the English Wikipedia contains approximately 500 portals.^[224] At least one portal for every academic discipline (10,000).
Wikimedia template (Q11266439): type of page in the Wikimedia system. Use with P31 'instance of' for template pages	`Enwiki:` 423,324 `Commons:` 6,095 `Wikidata:` 1,074,421 `Estimate:` 0	According to database reports, the English Wikipedia contains approximately 700,000 templates, while Wikimedia Commons includes about 135,000 templates.^[221]^[222]
Total	`Enwiki:` 3,729,708 `Commons:` 3,552,577 `Wikidata:` 9,242,608 `Estimate:` 9,246,571

Sister projects

The foundation operates other wiki-based content projects, also known as sister projects, that are written and governed by volunteer editors.

Sister project	Progress	References
Abstract Wikipedia Q96807071: software project by the Wikimedia Foundation to create a language-independent version of Wikipedia	`Content:` 0 `Estimate:` 9,025,925,491	At least one article for every element included in all the sections above (9,025,925,491). See meta:Abstract Wikipedia.
Wikibooks Q367: free multilingual online collection of textbooks	`Content:` 360,496 `Estimate:` 0	Pending estimate. See meta:Wikibooks.
Wikidata Q2013: free multilingual online knowledge graph	`Content:` 122,098,701 `Estimate:` 9,025,925,491	At least one item for every element included in all the sections above (9,025,925,491). See meta:Wikidata.
Wikifunctions Q104587954: Wikimedia project for a collaborative free catalog of computer functions	`Content:` 27,148 `Estimate:` 0	Pending estimate. See meta:Wikifunctions.
Wikimedia Commons Q565: online repository of free-use image, audio, and other media files	`Content:` 142,746,962 `Estimate:` 1,966,656,259	At least one picture of every notable person (8,000,000), every monument (5,000,000) and every populated place (20,000,000). One picture of every galaxy (2,459,296) and every star (1,811,709,771). At least one PDF/DJVU file of every book edition in the public domain (15,846,488). At least one picture, one sound recording and one video of every species (3x8,700,000=26,100,000). See meta:Wikimedia Commons.
Wikinews Q964: free online multilingual news	`Content:` 1,752,046 `Estimate:` 0	Wikinews was closed in 2026. See meta:Wikinews.
Wikiquote Q369: free multilingual online collection of quotes	`Content:` 375,736 `Estimate:` 0	At least one page for every notable person. Current estimates suggest there are 10 million notable individuals in Wikidata. See meta:Wikiquote.
Wikisource Q263: online multilingual library that collects open-content source material	`Content:` 8,981,352 `Estimate:` 1,500,000,000	At least one page for every page ever printed. If we assume there are 158,464,880 editions in existence, and only 10% are in the public domain, with an average length of 100 pages, that gives us roughly 1.5 billion pages. See meta:Wikisource.
Wikispecies Q13679: free multilingual online species directory	`Content:` 948,068 `Estimate:` 8,700,000	At least one page for every known species. Current estimates place global biodiversity at roughly 8,700,000 species. See meta:Wikispecies.
Wikiversity Q370: online multilingual collaborative project for learning materials	`Content:` 165,746 `Estimate:` 1,000,000	At least one course for every academic discipline, with 100 pages per course. Given an estimated 10,000 academic disciplines, the total output would be approximately 1 million pages. See meta:Wikiversity.
Wikivoyage Q373: free multilingual online travel guide	`Content:` 145,549 `Estimate:` 4,800,000	At least one page for every populated place, with an estimated 4.8 million such locations worldwide.^[225] See meta:Wikivoyage.
Wiktionary Q151: free online multilingual dictionary	`Content:` 48,773,520 `Estimate:` 700,000,000	At least one page for every word in every language: with an estimated 100,000 words per language and around 7,000 languages, this represents a potential corpus of 700 million dictionary entries. See meta:Wiktionary.

Non-described entities

Non-described entities are those known to exist, but for which we lack direct information. Nevertheless, they would become notable once we acquire knowledge about them.

For example, estimates for the total number of galaxies in the observable universe range from 200,000,000,000 (2×10¹¹) to 2,000,000,000,000 (2×10¹²), yet we do not have data for all of them.^[174]^[175] The same applies to stars: current estimates place the total number of stars in the observable universe between 10,000,000,000,000,000,000,000 (10²²) and 1,000,000,000,000,000,000,000,000 (10²⁴). Only a tiny fraction (<0.00000000001%) have been described, about 1,811,709,771 in the Gaia Data Release 3 from the Gaia European space mission.^[178]

This extends to other astronomical bodies such as exoplanets, asteroids, and comets, which populate every star system at roughly a 1000:1 ratio. Under this perspective, the potential number of items relevant to Wikidata exceeds 1,000,000,000,000,000,000,000,000,000 (10²⁷).

At this scale, adding any human-made creations, such as books, movies, or monuments, to the count becomes irrelevant for the overall estimate. Moreover, this estimate refers only to the observable universe. Whether the universe is infinite remains an open question in cosmology.

Non-notable entities

Non-notable entities are those known to exist but not included in Wikipedia or Wikidata due to notability criteria. We may or may not have information about them.

After counting galaxies and stars, one might assume that the next step would be to consider quantities such as the number of sand grains or atoms in the universe (≈10⁸⁰).^[227] However, there is something even better studied and vastly larger in scope: numbers. Some numbers have their own Wikipedia articles, but this is neither common nor remotely exhaustive. We could hardly create and store an item for every atom in the universe, and certainly not for every number. Yet there is a solution: items for any number and its mathematical properties can be generated dynamically.

Although many numbers may seem prosaic, some of the most interesting among them are prime numbers. As demonstrated by Euclid around 300 BC, there are infinitely many primes. As of 2024, the largest known prime number is 2^136,279,841 − 1, a Mersenne prime with 41,024,320 decimal digits:

881694327503833265553939100378117358971207354509066041067156
376412422630694756841441725990347723283108837509739959776874
... (41,024,200 digits skipped) ...
852806517931459412567957568284228288124096109707961148305849 349766085764170715060409404509622104665555076706219486871551^[228]

According to this approach, the potential number of items for Wikidata is $\infty$ infinite.

Lost knowledge

See Wikipedia:There is a deadline

Practically every day, unique forms of knowledge disappear forever with no surviving copies. When a natural disaster strikes or a war erupts, libraries, archives, museums, monuments and other cultural artifacts, including historic buildings, incunabula, and irreplaceable objects are destroyed or placed at serious risk. Such events often erase fragments of human knowledge and, in some cases, wipe out entire cultures.

Notes

↑ Articles that exists in English Wikipedia/Commons/Wikidata and estimate for this topic.

References

↑ 10,000,000,000,000,000 bytes archived!. 2012-10-26. Retrieved 2012-10-27. Archived. "On Thursday, 25 October, hundreds of Internet Archive supporters, volunteers, and staff celebrated addition of the 10,000,000,000,000,000th byte to the Archive’s massive collections."
↑ Mirroring Wikimedia project XML dumps. 2013-05-20. Retrieved 2013-05-20. Archived.
↑ Editing will temporarily pause for a failover test. 2017-04-18. Retrieved 2017-04-18. Archived.
↑ Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 7,206,436."
↑ Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 122,364,070."
↑ Special:MediaStatistics. Retrieved 2026-07-09. Archived. "144,280,788 files."
↑ Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 950,425."
↑ Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 8,913,723."
↑ Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 1,115,374."
↑ Wikimedia Downloads. Archived.
↑ meta:Mirroring Wikimedia project XML dumps
↑ Collection: Wikimedia downloads at Internet Archive.
↑ Collection: ZIM Archive at Internet Archive.
↑ Collection: The Wikimedia Commons Gargle at Internet Archive.
↑ GitHub Arctic Code Vault. Archived.
↑ Tech Tree. Archived. "[...] to help describe the overall cultural context in which this archive was created, a data dump of an entire 2020 snapshot of Wikipedia in the archive's five primary languages [...]"
↑ Vivian Maier. Archived.
↑ The Archive. 2009. Archived.
↑ Usenet Archive of UTZOO Tapes. 2001-12-11. Archived.
↑ A Dream to Preserve TV News, on the Road to Realization... with Your Help. 2013-11-22. Archived.
↑ About the Library of Congress. Retrieved 2026-06-13. Archived. "Recorded 178.2 million items in its collections, including: 25.77 million cataloged books in the Library of Congress classification system, 15.99 million items in the nonclassified print collections, including books in large type and raised characters, incunabula (books printed before 1501), monographs and serials, music, bound newspapers, pamphlets, technical reports and other printed material, 138.5 million items in the nonclassified (special) collections."
↑ Using the British Library. Retrieved 2015-02-24. Archived. "The British Library is the UK’s national library and one of the world’s leading research libraries. Our collection of around 170 million items includes some of the most iconic treasures from a variety of cultures and includes books, manuscripts, maps, newspapers, patents and sound recordings."
↑ Russian State Library. Retrieved 2026-06-13. Archived. "From the Rumyantsev Museum with a collection of 32,345 books to the country’s main library with collection holdings of up to 50 million items."
↑ Annual Report of the National Diet Library. Trends of the past year. 2008. Retrieved 2010-07-15. Archived.
↑ National Library of China - Visit Us. Overview of Library Collections. 2010. Retrieved 2012-09-28. Archived.
↑ BnF - ABC of the collections: N for Numerous. 2011-06-23. Retrieved 2015-02-24. Archived.
↑ ^27.000 ^27.001 ^27.002 ^27.003 ^27.004 ^27.005 ^27.006 ^27.007 ^27.008 ^27.009 ^27.010 ^27.011 ^27.012 ^27.013 ^27.014 ^27.015 ^27.016 ^27.017 ^27.018 ^27.019 ^27.020 ^27.021 ^27.022 ^27.023 ^27.024 ^27.025 ^27.026 ^27.027 ^27.028 ^27.029 ^27.030 ^27.031 ^27.032 ^27.033 ^27.034 ^27.035 ^27.036 ^27.037 ^27.038 ^27.039 ^27.040 ^27.041 ^27.042 ^27.043 ^27.044 ^27.045 ^27.046 ^27.047 ^27.048 ^27.049 ^27.050 ^27.051 ^27.052 ^27.053 ^27.054 ^27.055 ^27.056 ^27.057 ^27.058 ^27.059 ^27.060 ^27.061 ^27.062 ^27.063 ^27.064 ^27.065 ^27.066 ^27.067 ^27.068 ^27.069 ^27.070 ^27.071 ^27.072 ^27.073 ^27.074 ^27.075 ^27.076 ^27.077 ^27.078 ^27.079 ^27.080 ^27.081 ^27.082 ^27.083 ^27.084 ^27.085 ^27.086 ^27.087 ^27.088 ^27.089 ^27.090 ^27.091 ^27.092 ^27.093 ^27.094 ^27.095 ^27.096 ^27.097 ^27.098 ^27.099 ^27.100 ^27.101 ^27.102 ^27.103 ^27.104 ^27.105 ^27.106 ^27.107 ^27.108 ^27.109 ^27.110 ^27.111 ^27.112 ^27.113 ^27.114 ^27.115 ^27.116 ^27.117 ^27.118 ^27.119 ^27.120 ^27.121 ^27.122 ^27.123 ^27.124 ^27.125 ^27.126 ^27.127 ^27.128 ^27.129 ^27.130 ^27.131 ^27.132 ^27.133 ^27.134 ^27.135 ^27.136 ^27.137 ^27.138 ^27.139 ^27.140 ^27.141 ^27.142 ^27.143 ^27.144 ^27.145 ^27.146 ^27.147 ^27.148 ^27.149 ^27.150 ^27.151 ^27.152 ^27.153 ^27.154 ^27.155 ^27.156 ^27.157 Microsoft Copilot answer to the question: "How many XYZ are there in nature/the world/our galaxy/observable universe or occured in history? Please provide the most authoritative statistics available from recognized databases. If no definitive count exists, offer a well‑supported estimate."
↑ How Many Zoos and Aquariums Are There in the World: Uncovering Global Wildlife Facilities. 2025-03-25. Retrieved 2026-05-31. Archived. "There are roughly 1,100 aquariums worldwide, with North America hosting over 400 significant facilities."
↑ 2017 Infrastructure Report Card. Archived.
↑ Brücken: Zahlen, Daten, Fakten. 2019-06-24. Archived.
↑ Infrastruktura silniční dopravy v ČR a kraji k 1. 1. 2016. 2016-01-01. Archived.
↑ Lista de plazas de toros. Retrieved 2024-02-13. Archived.
↑ Is it Worth a Dam?. 1997. Retrieved 2013-05-20. Archived. "Worldwide, some 40,000 "large" dams (over 15 m high, according to the International Commission on Large Dams) and about 800,000 smaller ones have been constructed."
↑ Ranking Web of World Hospitals. 2015. Retrieved 2015-02-24. Archived. "The new edition is built from data collected in January 2015 for more than 16,500 Hospitals websites from all over the World."
↑ Total number of hospitals globally from 2021 to 2026. 2026. Retrieved 2026-06-08. Archived. "By 2026, the number of hospitals worldwide is projected to reach 215,977."
↑ Number of hotels and other accommodation establishments. Data by Countries from 1995 to 2024. Retrieved 2026-06-10. Archived. "Total: 817,196. Countries: 188."
↑ How many hotels in the world are there anyway? Booking.com keeps adding them. 2013-05-22. Retrieved 2013-05-22. Archived. "Booking.com says it offers 202,842 hotels globally. STR Global estimates that there are 187,000 hotels, offering 17.5 million guest rooms, around the globe. Other less-than-scientific guesstimates put the number of hotels around the world at around 400,000, with an additional 100,000 or so if you include B&Bs and hostels etc. In a similar vein, one of the global distribution systems informally uses 500,000 as a guide to the number of hotels in the world, although this number would exclude hostels, guest houses and motels."
↑ The Lighthouse Directory. Archived. "Welcome to the Lighthouse Directory, providing information and links for more than 24,400 of the world's lighthouses."
↑ List of cathedrals in Wikidata.
↑ Catholicism: How many physical Catholic churches are there in the world?. Archived.
↑ How many churches are there in the world?. Archived.
↑ Fun Fact: There are more churches (450,000) in the USA than there are convenience stores (146,341), fast food restaurants (160,000), and hotels/motels (46,295, not counting casino hotels) combined (352,636 total).. Archived.
↑ How Many Mosques Are There in the World?. Retrieved 2014-08-06. Archived.
↑ How many Mosques are there in the world?. Retrieved 2014-08-06. Archived.
↑ Global Integrated Power Tracker. Retrieved 2026-06-10. Archived. "200 country/areas included, 22,296 gigawatts of capacity covered, 182,400 power facilities tracked, 8,000+ facility owners."
↑ US has more prisoners, prisons than any other country. 2012-10-15. Archived.
↑ Global REservoir Inventory (GREI). 2025-01-08. Retrieved 2026-06-08. Archived. "GREI documents 556,063 reservoirs across six continents of the world, with a total water surface area of 469,497.10 km² and net water storage capacity of 7,563.04 ± 752.65 km³ (excluding human-regulated lakes with a total capacity of 626.80 km3). GREI includes a significant number of small reservoirs (herein classified as <1 km²) that are underreported in existing global reservoir datasets. Specifically, GREI compiles 39 times more small reservoirs than the recently released and widely used GeoDAR v1.1 dataset. Small reservoirs dominate the global distribution in count (95.38%) but contribute only 4.73% to total storage capacity. In contrast, medium-sized (1–10 km2) and large (≥10 km2) reservoirs account for only 3.84% and 0.78% by count but represent 8.62% and 86.65% of the global net capacity, respectively."
↑ SkyscraperPage.com. 2013-05-20. Retrieved 2013-05-20. Archived. "93,962 Structures (2013), 89,160 Structures (2012), 72,609 Structures (2010)."
↑ Stadiums in the United States. 2013-05-20. Retrieved 2013-05-20. Archived.
↑ Ranking Web of World Universities. Archived.
↑ Zoos by Country 2024. Retrieved 2024-02-13. Archived. "The American Zoo and Aquarium Association (AZA) reports a staggering 10,000 zoos worldwide, reflecting the global popularity of these wildlife sanctuaries."
↑ ^52.0 ^52.1 ^52.2 IMDb Database Statistics. Retrieved 2026-06-09. Archived. "Titles: 28,120,305; Names: 15,211,214."
↑ ^53.0 ^53.1 How Many TV and Radio Stations are There?. 2011. Retrieved 2013-05-21. Archived. "As on March 2011: 14,728 full power radio stations: 4,778 AM, 6533 FM, and 3,417 educational FM. There are 859 Low Power FM stations. 1,774 full power TV stations: 1,022 UHF commercial, 360 VHF commercial, 285 UHF educational, and 107 VHF educational. 10,595 translators and booster stations. 2,172 low power TV stations."
↑ ^54.0 ^54.1 The wonder that is media. 2013-05-21. Retrieved 2013-05-21. Archived. "There are over 72,000 publications currently registered with the Registrar of Newspapers of India. At present, over 700 TV channels have been permitted by the Ministry of Information and Broadcasting to uplink or downlink from the country."
↑ Croissance du nombre de chaînes et de plates-formes de télévision européennes malgré la crise. 2010-01-13. Retrieved 2013-05-21. Archived. "Plus de 245 nouvelles chaînes de télévision ont été lancées en Europe en 2009 ; ce qui mène à la fin de l’année 2009 à un total de 7 200 chaînes de télévision européennes."
↑ How many radio stations are there in the world?. 2013-05-21. Retrieved 2013-05-21. Archived. "There are about 44,000 radio stations worldwide."
↑ Mapping the global landscape of journals. Retrieved 2026-06-13. Archived. "Our preliminary dataset is aggregated from five local and global information sources including a total of 152,644 unique journals matched with bibliographic metadata records from the International ISSN Centre."
↑ Article 50 million: An estimate of the number of scholarly articles in existence. Archived.
↑ ScienceOpen. Retrieved 2024-02-12. Archived. "91 million publications, 25,000 journals, 32 million authors."
↑ Europe PubMed Central. Retrieved 2026-06-08. Archived. "Research articles (48,250,198)."
↑ Scholia Statistics. Archived.
↑ Internet Archive Scholar. Retrieved 2024-02-12. Archived. "This fulltext search index includes over 35 million research articles and other scholarly documents preserved in the Internet Archive. The collection spans from digitized copies of eighteenth century journals through the latest Open Access conference proceedings and preprints crawled from the World Wide Web."
↑ IET Inspec. Retrieved 2026-06-08. Archived. "It contains over 27 million records of research literature from hundreds of trusted global publishers."
↑ PubMed Central. Retrieved 2026-06-08. Archived. "12.1 million articles are archived in PMC."
↑ Compendex on Engineering Village. Retrieved 2026-06-08. Archived. "10.3M+ papers from 150,000+ conference proceedings."
↑ About IEEE Xplore. Retrieved 2024-02-12. Archived. "IEEE Xplore contains more than 6 million documents and other materials from some of the world's most cited publications in electrical engineering, computer science, and related sciences. The content in IEEE Xplore comprises: Over 1.5 million research articles, Over 4 million conference papers, Over 14,000 technical standards, Over 66,000 books and book chapters, Over 500 online educational courses. Approximately 25,000 new content items are added to IEEE Xplore each month."
↑ arXiv.org. Retrieved 2024-02-12. Archived. "arXiv is a free distribution service and an open-access archive for nearly 2.4 million scholarly articles in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics."
↑ Open Access Theses and Dissertations. Retrieved 2026-06-08. Archived. "OATD.org aims to be the best possible resource for finding open access graduate theses and dissertations published around the world. Metadata (information about the theses) comes from over 1100 colleges, universities, and research institutions. OATD currently indexes 7,464,811 theses and dissertations."
↑ Grand Comics Database. Retrieved 2026-06-08. Archived. "Total: 2,189,540 issues."
↑ "Dictionary" search on Open Library.
↑ "Encyclopedia" search on Open Library.
↑ The ARTFL Encyclopédie
↑ Books of the world, stand up and be counted! All 129,864,880 of you. 2010-08-05. Retrieved 2010-08-05. Archived. "After we exclude serials, we can finally count all the books in the world. There are 129,864,880 of them. At least until Sunday."
↑ How Many Books Are In The World?. Archived.
↑ Incunabula Short Title Catalogue. 2013-05-21. Retrieved 2013-05-21. Archived. "The database records nearly every item printed from movable type before 1501, but not material printed entirely from woodblocks or engraved plates. 29,777 editions are listed as at January 8th 2008, including some 16th-century items previously assigned incorrectly to the 15th century."
↑ Universal Short Title Catalogue. Archived.
↑ ^77.0 ^77.1 Mass Media. Archived.
↑ MusicBrainz - Database statistics. Retrieved 2026-06-12. Archived. "Releases: 5,562,960."
↑ Discogs - search. Retrieved 2015-11-04. Archived.
↑ Business Matters: 75,000 Albums Released In U.S. In 2010 — Down 22% From 2009. 2011-02-18. Archived.
↑ El arte rupestre mundial y el arte rupestre como Patrimonio de la Humanidad. Retrieved 2026-07-06. Archived. "To date, some 100,000 prehistoric works of art have been found and registered, including objects. Most of these examples of rock art are distributed among 700,000 sites around the world, with paintings and engravings that contain some 20 million images. To date, 99% of the prehistoric art discovered is rock art."
↑ BBC - Your Paintings. Retrieved 2015-11-04. Archived.
↑ Le incisioni rupestri... segni del pensiero. Retrieved 2026-07-07. Archived. "The global census carried out by different research groups estimates that over 300,000 rock engravings are currently known. Thanks to continuous discoveries, this number is expected to increase progressively."
↑ United Nations Member States. Archived.
↑ Caves of the world. 2013-05-26. Retrieved 2013-05-26. Archived. "Number of caves = 2424; Caves deeper than 300m = 1075; Caves longer than 3kms = 1628."
↑ Mapping the World’s Glaciers. Archived.
↑ Kyrgyzstan Glaciers. Archived. "Glaciers, (8000 of them – one source says 8208), and permanent snow cover some 8100 square kilometers - about 30% of the total land area of the Kyrgyz Republic. The glaciers themselves cover about 4% of the surface area of the country."
↑ How many Alaska glaciers? No easy answer. Retrieved 2014-07-27. Archived. "Not long ago, a glaciologist wrote that the number of glaciers in Alaska "is estimated at (greater than) 100,000." That fuzzy number, perhaps written in passive voice for a reason, might be correct. But it depends upon how you count."
↑ Alaska's Glaciers. Archived. "745 Feature records have been selected from GNIS."
↑ Earth's many new lakes. Retrieved 2026-06-11. Archived. "The number of lakes on our planet has increased substantially in recent decades, according to a unique global survey of 3.4 million lakes. There has been a particular increase in the number of small lakes, which unfortunately, emit large amounts of greenhouse gas. The development is of great importance for Earth's carbon account, global ecosystems, and human access to water resources."
↑ Belarus Overview. Archived. "There are more than 20,000 rivers and creeks and about 11,000 lakes in Belarus."
↑ The Atlas of Canada. Archived. "31,752+larger than 3 km² (2-3 million in total)."
↑ Which country has the most lakes?. Archived.
↑ Lakes in Finland. Archived. "There are 187,888 lakes in Finland. Lake is here defined as a body of standing water larger than 5 ares (500 m2). 56,000 over 10,000 m²."
↑ Data available for 150,000, only 75,000 with name, 57,000 in sv:Kategori:Listor över Sveriges insjöar.
↑ Mountains Mount. 2012-05-30. Retrieved 2013-05-26. Archived.
↑ HydroRIVERS. Retrieved 2026-06-11. Archived. "The global coverage of HydroRIVERS encompasses 8.5 million individual river reaches with an average length of 4.2 km, representing a total of 35.9 million km of rivers globally."
↑ Cartographic river drainage databases. Archived.
↑ More than half of Europe's rivers fail ecological targets, report finds. Archived.
↑ According to unknown sources there are 8,188 rivers less than 25 km, only 24 rivers over 100 km.
↑ National Aquaculture Sector Overview - Brazil. Archived.
↑ China - Geography and population. Archived.
↑ 28,000 Rivers Disappeared in China: What Happened?. Archived.
↑ El Salvador - Physical Features. Archived.
↑ HYDRO ENERGY. Archived.
↑ Hydropower, indigenous peoples’ rights and popular resistance in Guatemala. Archived.
↑ Water and hydropower Resources of the Kyrgyz Republic. Archived.
↑ Воды. Archived. "2,044 over 10 km."
↑ Nepal River Conservation Trust. Archived. "The latest data shows that Nepal has got over 6000 rivers and streams which have got hydropower potential."
↑ Panama - Geography. Archived. "Nearly 500 rivers lace Panama's rugged landscape. Mostly unnavigable, many originate as swift highland streams, meander in valleys, and form coastal deltas."
↑ Inland fisheries of Europe. Archived. "In addition to the dominating Danube, Romania has over 4,000 rivers having watersheds larger than 10 km2 and a total length exceeding 60,000 km."
↑ Russia:: Rivers and Lakes. Archived. "Among its 100,000 rivers, Russia contains some of the world's longest. Four of the country's five longest rivers—the Ob-Irtysh, Amur, Lena, and Yenisey—are in Siberia."
↑ Russia - Water report. Archived. "There are 120,000 rivers over 10 km long. Their total length within the Russian Federation equals 2.3 million km."
↑ Spain - Rivers. Archived. "Of the roughly 1,800 rivers and streams in Spain, only the Tagus is more than 960 kilometers long; all but 90 extend less than 96 kilometers."
↑ FAO Fishery Country Profile - UKRAINE. Archived. "Ukraine has about 71,000 rivers, with a total length of 248,000 km. Among them, 3,212 rivers have a length of more than 10 km and total 73,700 km in length."
↑ River Facts. Archived.
↑ Wikipedia talk:WikiProject Rivers. Archived. "2,000,000+ including small streams."
↑ Venezuela - Rivers. Archived. "The Orinoco is by far the most important of the more than 1,000 rivers in the country."
↑ How many volcanoes are there in the world?. Archived.
↑ EventKG - A Multilingual Event-Centric Temporal Knowledge Graph. Retrieved 2026-06-20. Archived. "The EventKG is a multilingual resource incorporating event-centric information extracted from several large-scale knowledge graphs such as Wikidata, DBpedia and YAGO, as well as less structured sources such as the Wikipedia Current Events Portal and Wikipedia event lists in 15 languages. EventKG provides information for over 1.3 million events and over 4.5 million temporal relations."
↑ Censo-Guía de Archivos de España e Iberoamérica. Archived.
↑ ^122.0 ^122.1 ^122.2 Libraries, Archives, Museums and Publishing Online Statistics Tables. Archived.
↑ OCLC President’s Report. Archived.
↑ Burundi - Libraries and museums. Archived. "There are 60 public libraries in Burundi, with the largest in and around the capital. Libraries in Bujumbura include the Public Library, which has 27,000 volumes; the library of the University of Burundi, with 192,000 volumes; and a specialized collection at the Department of Geology and Mines. The French Cultural Center in Bujumbura holds 33,000 volumes."
↑ How many libraries are in Canada?. Archived.
↑ Croatia - Libraries and museums. Archived. "In 1995, the country reported having 232 public libraries with a combined collection of 4.6 million volumes."
↑ Cuba cuenta con más de 400 bibliotecas públicas en todo el territorio nacional, incluidas las situadas en las montañas. Archived.
↑ Czech Republic - Libraries and museums. Archived. "In 1997, the Czech Republic had 6,245 public libraries with 53.7 million volumes and 1.4 million registered users."
↑ Denmark - Libraries and museums. Archived. "As of 2002, there were 250 free public libraries throughout the country with 892 points of service. That year, the public libraries had a total of more than 31.4 million volumes."
↑ Finland - Libraries and museums. Archived. "There are about 400 research and university libraries in Finland, most of which are small. In 1997 there were 436 central public libraries and 1,202 branch libraries."
↑ ^131.0 ^131.1 Report on the situation of libraries, museums and archive. Archived. "In Finland there were 439 public libraries having 1006 branches and 370 research libraries with 465 branches in 1996. The total number of library units was 1471. The total number of museums in Finland is 280, of which 139 are cultural history museums, 71 special museums, 55 art museums and 17 natural history museums."
↑ ^132.0 ^132.1 France - Libraries and museums. Archived. "In 1997 there were 1,620 central public libraries with a combined total of more than 89.8 million volumes. There are more than 1,000 museums in France."
↑ FYI France. Archived.
↑ ^134.0 ^134.1 Germany - Libraries and museums. Archived. "As of 1997, Germany had 6,313 public libraries with 149 million volumes in total. Germany has more than 4,500 state, municipal, association, private, residential, castle, palace, and church and cathedral treasures museums, which annually attract over 100 million visitors."
↑ Greece - Libraries and museums. Archived. "In 1997, there were 672 public libraries with a total of 9.1 million volumes."
↑ ^136.0 ^136.1 Hungary - Libraries and museums. Archived. "As of 1997, there were 3,518 regional public libraries located throughout the country. There were over 500 museums (about 70 in Budapest) and many zoological and botanical gardens."
↑ ^137.0 ^137.1 Iceland - Libraries and museums. Archived. "There were a total of 187 public libraries with combined holdings of 1.9 million volumes in 1997. Iceland has more than 50 museums."
↑ Latvia - Libraries and museums. Archived. "In 1997, the country counted 998 public libraries housing 14.9 million volumes."
↑ Lithuania - Libraries and museums. Archived. "In 1997, there were 1,478 public libraries in the country."
↑ ^140.0 ^140.1 Morocco - Libraries and museums. Archived. "Of the 18 public libraries in Morocco, the largest is in Casablanca, with almost 360,000 volumes."
↑ Netherlands - Libraries and museums. Archived. "In 1997 there were 579 main public libraries with a combined collection of 41.5 million books."
↑ Korea, Democratic People's Republic of (DPRK) - Libraries and museums. Archived. "The DPRK has more than 200 public libraries, the largest being the Grand People's Study House in P'yongyang, with 20 million volumes."
↑ Norway - Libraries and museums. Archived. "Norway's 1,108 public libraries had 20.5 million volumes in 1997."
↑ Panama - Libraries and museums. Archived. "There are more than 40 other public libraries and branches."
↑ ^145.0 ^145.1 Peru - Libraries and museums. Archived. "There are nearly 200 public libraries in Peru, the largest of them in Callao, Arequipa, and Lima. More than 250 public and private museums."
↑ ^146.0 ^146.1 Poland - Libraries and museums. Archived. "In 1997 there were 9,230 public libraries, jointly holding almost 135 million volumes. Of the more than 500 museums in Poland..."
↑ ^147.0 ^147.1 Portugal - Libraries and museums. Archived. "In 1997 the country had 168 public libraries with 4.8 million volumes. There are some 300 museums in Portugal."
↑ ^148.0 ^148.1 Romania - Libraries and museums. Archived. "In 1997, the country had over 2,950 public libraries holding a total collection of 50.5 million volumes. Romania has some 400 museums."
↑ ^149.0 ^149.1 Russia - Libraries and museums. Archived. "In 1995, the country counted 50,032 public libraries, holding in total 983.4 million volumes. Russia has over 1,000 museums."
↑ ^150.0 ^150.1 Sweden - Libraries and museums. Archived. "In 1997, Sweden had 324 public libraries. Sweden has about 200 museums."
↑ Tanzania - Libraries and museums. Archived. "The Tanzania Library Service was established in 1964. It maintains the National Central Library in Dar es Salaam (656,000 volumes), 16 public libraries, school library service, and a rural extension service."
↑ Tunisia - Libraries and museums. Archived. "The collections of Tunisia's approximately 250 public libraries hold over 2.7 million volumes."
↑ Ukraine - Libraries and museums. Archived. "In 1995, there were reported to be 21,857 public libraries operating in Ukraine with an overall stock of 336.7 million books."
↑ Library Copyright Alliance. Archived.
↑ Zimbabwe - Libraries and museums. Archived. "There were more than 150,000 registered public library users using 76 public libraries holding 1.1 million volumes in 1989. In 1990, 100,000 people visited Zimbabwe's 11 museums."
↑ Books, manuscripts, journals, newspapers, magazines, sound and music recordings, videos, play-scripts, patents, databases, maps, stamps, prints, drawings. 14 million are books, 3 million recordings. See also British Library Sound Archive.
↑ About the Smithsonian. Archived.
↑ Carl Malamud Answers: Goading the Government To Make Public Data Public. Archived.
↑ Museums worldwide - statistics & facts. Archived. "According to the latest estimates by UNESCO, there were nearly 104,000 such organizations globally, with the regions of North America and Western Europe reporting the highest number of museums worldwide."
↑ Frequently Asked Questions. Archived.
↑ The Cost of Digitising Europe's Cultural Heritage. Archived. "there are approximately 17,673 museums in Europe, based on figures submitted between 2003 and 2008."
↑ Arts and Culture in Australia: A Statistical Overview, 2010. Archived. "According to Museums, Australia, 2007-08 (cat. no. 8560.0) there were 1,019 museums operating from 1,276 locations in Australia at the end of June 2008. These locations included 768 social history museums, 425 historic properties and sites, and 83 other museums."
↑ Interesting Facts About Canadian Museums. Archived. "Canada has more than 2,400 museums, which have more than 24,000 paid employees and 55,000 volunteers, and receive nearly 54 million visits annually."
↑ Museums in Germany – where history and culture are brought to life. Archived. "The 4,000 or so museums in Germany serve as worlds of discovery and use exciting concepts to explore art and history, technology and architecture, literature and the natural world."
↑ How many museums in Pakistan?. Archived.
↑ Visit museums in Spain. Archived.
↑ Frequently asked questions. Archived. "It is estimated that there are about 2,500 museums in the UK, depending on what you include. Over 1,800 museums have been accredited by the Museums, Libraries and Archives Council (MLA)."
↑ How many museums are there in the United States?. Archived.
↑ Atlas database. Archived.
↑ Natural history museums around the globe contain over 1.1 billion objects. Retrieved 2026-06-13. Archived. "They have looked at the collections held in 73 museums found in 28 countries and discovered that collectively these institutions hold some 1,147,934,687 objects."
↑ Webaldic. Retrieved 2026-06-21. Archived. "With over 6 million coats of arms, indexed and searchable in one database, Webaldic helps you uncover the identity and meaning of coats of arms."
↑ Flags of the World. Retrieved 2026-06-21. Archived. "Flags of the World (FOTW), founded in 1994, is the Internet’s largest site devoted to vexillology (the study of flags). Here you can read more than 90,000 pages about flags and view more than 223,000 images of flags of countries, organizations, states, territories, districts and cities, both past and present."
↑ Gigantes. Retrieved 2026-06-13. Archived. "Gigantes is the most extensive and realistic void catalog suite ever released, containing over 1 billion cosmic voids covering a volume larger than the observable universe, more than 20 TB of data, and created by running the void finder VIDE on the halos from the Quijote simulations. Gigantes provides the tools for intensive machine learning exploration of void statistics."
↑ ^174.0 ^174.1 Astronomers were wrong about the number of galaxies in universe. 2021-01-14. Archived.
↑ ^175.0 ^175.1 How many galaxies are in the universe? A lot more than you'd think. 2023-07-25. Archived.
↑ Researchers launch REGALADE: The most complete galaxy catalogue for modern astronomy. Retrieved 2026-06-11. Archived. "An international team of scientists has introduced REGALADE (Revised Galaxy List for the Advanced Detector Era), an unprecedented all-sky catalogue that brings together nearly 80 million galaxies."
↑ Euclid Telescope Discerns 26 Million Galaxies in New Update of Sky Map. Retrieved 2026-06-11. Archived. "With one scan of each deep field, Euclid has been able to spot 26 million galaxies, the farthest of which lie 10.5 billion light-years away. To classify this deluge of cosmic data, the ESA has called upon citizen scientists to help classify the galaxies with some assistance from AI algorithms. More than 380,000 galaxies have been classified so far, but this amount is just one drop of a colossal data pool that will bring images of 1.5 billion galaxies to light over the next few years."
↑ ^178.0 ^178.1 Gaia Archive. Archived.
↑ ^179.0 ^179.1 ^179.2 JPL Solar System Dynamics. Archived.
↑ How Many Species Are There on Earth and in the Ocean?. Archived.
↑ The Biology of Rarity: Causes and consequences of rare—common differences. Retrieved 2015-05-26. Archived.
↑ Watching, from the Edge of Extinction. Retrieved 2017-05-30. Archived.
↑ Prehistory’s Brilliant Future. 2014-11-08. Retrieved 2014-12-25. Archived.
↑ Newman, Mark. A model of mass extinction. 1997. Journal of Theoretical Biology 189: 235–252.
↑ UniProtKB statistics. Retrieved 2026-06-10. Archived. "Number of entries in total: 149,810,139."
↑ Expanding and Enriching the LncRNA Gene–Disease Landscape Using the GeneCaRNA Database. Retrieved 2026-06-11. Archived. "The GeneCaRNA human gene database is a member of the GeneCards Suite. It presents 280,000 human non-coding RNA genes, identified algorithmically from 690,000 RNAcentral transcripts. This expands by tenfold the ncRNA gene count relative to other sources. GeneCaRNA thus contains ~120,000 long non-coding RNAs (LncRNAs, >200 bases long), including 100,000 novel genes."
↑ CAS REGISTRY. Retrieved 2026-06-12. Archived. "CAS REGISTRY is a database of disclosed chemical substances curated from scientific literature and other sources. It contains over 290 million substances and is continuously enhanced with new substances."
↑ PubChem Data Counts. Retrieved 2026-06-12. Archived. "Compounds: 123,914,913. Unique chemical structures extracted from contributed PubChem Substance records."
↑ How Many Chemical Compounds Are There?. Retrieved 2026-06-12. Archived. "The number of chemical substances formally documented and registered stands at an astonishing scale. The primary global registry identifies over 290 million unique substances, a figure that grows by approximately 15,000 new substances every day, reflecting rapid global research and discovery. Much of this growth comes from organic chemistry, involving carbon-based molecules, and the complex field of biopolymers."
↑ CAS REACTIONS. Retrieved 2026-06-12. Archived. "The CAS reactions collection provides detailed and dependable data on more than 150 million single and multi-step reactions."
↑ Cambridge Structural Database (CSD). Retrieved 2026-06-12. Archived. "Established in 1965 with historical structures dating back to the 1920s, the Cambridge Structural Database (CSD) is the world’s largest curated repository of experimental crystal structures. It contains over 1.4 million accurate 3D structures derived from X-ray, neutron, and electron diffraction analyses. The database is used by researchers across the pharmaceutical, agrochemical, and fine chemicals industries to predict and guide future discoveries."
↑ Particle Data Group. Retrieved 2026-06-12. Archived.
↑ The On-Line Encyclopedia of Integer Sequences (OEIS). Retrieved 2026-06-13. Archived. "Contains 396,547 sequences."
↑ ClinicalTrials.gov. Retrieved 2026-06-12. Archived. "ClinicalTrials.gov is a place to learn about 589,453 studies with locations in all 50 states and in 226 countries and territories."
↑ Measuring Diagnoses: ICD Code Accuracy. Archived.
↑ How many drug targets are there?. Archived. "1,357 unique drugs: 1,204 are 'small-molecule drugs' and 166 are 'biological' drugs."
↑ Biographies by gender in Wikidata.
↑ Worldometers - real time world statistics. Archived.
↑ How Many People Have Ever Lived on Earth?. Archived.
↑ Occupations in Wikidata.
↑ ^201.0 ^201.1 About Forebears Names. Retrieved 2026-06-12. Archived. "Forebears Names is a free service providing access to the largest geospatial database of forename and surname distribution and demographics. It provides the approximate incidence of forenames and surnames produced from a database of 4,044,546,938 people (55.5% of living people in 2014). As of September 2019 it covers 27,662,801 forenames and 27,206,821 surnames in 236 jurisdictions."
↑ Unicode Version 17.0 Character Counts. Retrieved 2026-06-21. Archived. "Total Assigned: 297,334."
↑ How Many Companies Are There? NEW 2025 Statistics. Retrieved 2026-06-12. Archived. "There are around 359 million companies worldwide. There are 33.2 million businesses in the US. Small businesses make up 90% of all businesses globally. Approximately 100 million new businesses start each year worldwide."
↑ India: More NGOs, than schools and health centres. 2010-07-07. Retrieved 2011-10-07. Archived.
↑ First official estimate: An NGO for every 400 people in India. 2010-07-07. Archived.
↑ Hobbled NGOs wary of Medvedev. 2008-05-07. Archived.
↑ Fact Sheet: Non-Governmental Organizations (NGOs) in the United States. Archived.
↑ Adherents.com. 2013-05-23. Retrieved 2013-05-24. Archived. "Adherents.com is a growing collection of over 43,870 adherent statistics and religious geography citations: references to published membership/adherent statistics and congregation statistics for over 4,200 religions, churches, denominations, religious bodies, faith groups, tribes, cultures, movements, ultimate concerns, etc."
↑ Let's Document all the File Formats!. Retrieved 2026-06-13. Archived. "Statistics: 6,667 articles."
↑ Museum of Obsolete Media. Retrieved 2026-06-13. Archived. "A unique online museum of physical media formats showcasing developments in audio, video, film and data storage."
↑ Viruses Expected to Hit 1 Million This Year. 2008-04-06. Archived.
↑ App Store's 25 Billionth Download Comes From China with 'Where's My Water? Free'. Archived.
↑ Google Play About To Pass 15 Billion App Downloads? Pssht! It Did That Weeks Ago. 2012-05-07. Retrieved 2012-05-22. Archived.
↑ Global Aviation Statistics. Retrieved 2026-06-10. Archived. "84,330 airports, 179,932 flight routes, 249 countries, 1,431 airlines."
↑ mborsetti/airportsdata. Retrieved 2026-06-10. Archived. "Extensive database of current data for nearly every airport and landing strip in the world, with over 28,000 entries."
↑ The Global Airport Database. Retrieved 2026-06-10. Archived. "The Global Airport Database (GADB) is a free downloadable database of 9,300 airports big and small from all around the world."
↑ Ports Directory. Retrieved 2026-06-09. Archived. "This directory covers 20,559 ports across 236 countries and territories, each identified by its UN/LOCODE."
↑ World Port Directory. Retrieved 2026-06-09. Archived. "19,445 ports — Search by name, country or UN/LOCODE."
↑ The World Factbook — COUNTRY COMPARISON :: ROADWAYS. Archived.
↑ SIC 1622: BRIDGE, TUNNEL, AND ELEVATED HIGHWAY CONSTRUCTION. Archived. "Of the more than 600,000 bridges in the United States, 45 percent are under the financial jurisdiction of state governments, and 38 percent are controlled by county authorities."
↑ ^221.0 ^221.1 ^221.2 Wikipedia:Database reports/Page count by namespace.
↑ ^222.0 ^222.1 ^222.2 Commons:Database reports/Page count by namespace.
↑ Category:Disambiguation pages.
↑ Wikipedia:Contents/Portals.
↑ About GeoNames. Retrieved 2026-06-15. Archived. "The GeoNames geographical database is available for download free of charge under a creative commons attribution license. It contains over 25 million geographical names and consists of over 12 million unique features whereof 4.8 million populated places and 16 million alternate names."
↑ Alien Life Imagined: Communicating the Science and Culture of Astrobiology. Archived.
↑ Atoms in the Universe. Archived.
↑ 52nd Known Mersenne Prime Discovered. Archived.

External links

This user wants to compile and preserve the sum of all human knowledge.

Wikidata project and its query service

[column_progress-27] Articles that exists in English Wikipedia/Commons/Wikidata and estimate for this topic.

[1] 10,000,000,000,000,000 bytes archived!. 2012-10-26. Retrieved 2012-10-27. Archived. "On Thursday, 25 October, hundreds of Internet Archive supporters, volunteers, and staff celebrated addition of the 10,000,000,000,000,000th byte to the Archive’s massive collections."

[2] Mirroring Wikimedia project XML dumps. 2013-05-20. Retrieved 2013-05-20. Archived.

[3] Editing will temporarily pause for a failover test. 2017-04-18. Retrieved 2017-04-18. Archived.

[4] Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 7,206,436."

[5] Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 122,364,070."

[6] Special:MediaStatistics. Retrieved 2026-07-09. Archived. "144,280,788 files."

[7] Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 950,425."

[8] Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 8,913,723."

[9] Special:Statistics. Retrieved 2026-07-09. Archived. "Content pages: 1,115,374."

[10] Wikimedia Downloads. Archived.

[11] ta:Mirroring Wikimedia project XML dumps

[12] Collection: Wikimedia downloads at Internet Archive.

[13] Collection: ZIM Archive at Internet Archive.

[14] Collection: The Wikimedia Commons Gargle at Internet Archive.

[15] GitHub Arctic Code Vault. Archived.

[16] Tech Tree. Archived. "[...] to help describe the overall cultural context in which this archive was created, a data dump of an entire 2020 snapshot of Wikipedia in the archive's five primary languages [...]"

[17] Vivian Maier. Archived.

[18] The Archive. 2009. Archived.

[19] Usenet Archive of UTZOO Tapes. 2001-12-11. Archived.

[20] A Dream to Preserve TV News, on the Road to Realization... with Your Help. 2013-11-22. Archived.

[21] About the Library of Congress. Retrieved 2026-06-13. Archived. "Recorded 178.2 million items in its collections, including: 25.77 million cataloged books in the Library of Congress classification system, 15.99 million items in the nonclassified print collections, including books in large type and raised characters, incunabula (books printed before 1501), monographs and serials, music, bound newspapers, pamphlets, technical reports and other printed material, 138.5 million items in the nonclassified (special) collections."

[bl_ff-22] Using the British Library. Retrieved 2015-02-24. Archived. "The British Library is the UK’s national library and one of the world’s leading research libraries. Our collection of around 170 million items includes some of the most iconic treasures from a variety of cultures and includes books, manuscripts, maps, newspapers, patents and sound recordings."

[rsl-23] Russian State Library. Retrieved 2026-06-13. Archived. "From the Rumyantsev Museum with a collection of 32,345 books to the country’s main library with collection holdings of up to 50 million items."

[ndl-24] Annual Report of the National Diet Library. Trends of the past year. 2008. Retrieved 2010-07-15. Archived.

[25] National Library of China - Visit Us. Overview of Library Collections. 2010. Retrieved 2012-09-28. Archived.

[26] BnF - ABC of the collections: N for Numerous. 2011-06-23. Retrieved 2015-02-24. Archived.

[c-28] 27.000 ^27.001 ^27.002 ^27.003 ^27.004 ^27.005 ^27.006 ^27.007 ^27.008 ^27.009 ^27.010 ^27.011 ^27.012 ^27.013 ^27.014 ^27.015 ^27.016 ^27.017 ^27.018 ^27.019 ^27.020 ^27.021 ^27.022 ^27.023 ^27.024 ^27.025 ^27.026 ^27.027 ^27.028 ^27.029 ^27.030 ^27.031 ^27.032 ^27.033 ^27.034 ^27.035 ^27.036 ^27.037 ^27.038 ^27.039 ^27.040 ^27.041 ^27.042 ^27.043 ^27.044 ^27.045 ^27.046 ^27.047 ^27.048 ^27.049 ^27.050 ^27.051 ^27.052 ^27.053 ^27.054 ^27.055 ^27.056 ^27.057 ^27.058 ^27.059 ^27.060 ^27.061 ^27.062 ^27.063 ^27.064 ^27.065 ^27.066 ^27.067 ^27.068 ^27.069 ^27.070 ^27.071 ^27.072 ^27.073 ^27.074 ^27.075 ^27.076 ^27.077 ^27.078 ^27.079 ^27.080 ^27.081 ^27.082 ^27.083 ^27.084 ^27.085 ^27.086 ^27.087 ^27.088 ^27.089 ^27.090 ^27.091 ^27.092 ^27.093 ^27.094 ^27.095 ^27.096 ^27.097 ^27.098 ^27.099 ^27.100 ^27.101 ^27.102 ^27.103 ^27.104 ^27.105 ^27.106 ^27.107 ^27.108 ^27.109 ^27.110 ^27.111 ^27.112 ^27.113 ^27.114 ^27.115 ^27.116 ^27.117 ^27.118 ^27.119 ^27.120 ^27.121 ^27.122 ^27.123 ^27.124 ^27.125 ^27.126 ^27.127 ^27.128 ^27.129 ^27.130 ^27.131 ^27.132 ^27.133 ^27.134 ^27.135 ^27.136 ^27.137 ^27.138 ^27.139 ^27.140 ^27.141 ^27.142 ^27.143 ^27.144 ^27.145 ^27.146 ^27.147 ^27.148 ^27.149 ^27.150 ^27.151 ^27.152 ^27.153 ^27.154 ^27.155 ^27.156 ^27.157 Microsoft Copilot answer to the question: "How many XYZ are there in nature/the world/our galaxy/observable universe or occured in history? Please provide the most authoritative statistics available from recognized databases. If no definitive count exists, offer a well‑supported estimate."

[29] How Many Zoos and Aquariums Are There in the World: Uncovering Global Wildlife Facilities. 2025-03-25. Retrieved 2026-05-31. Archived. "There are roughly 1,100 aquariums worldwide, with North America hosting over 400 significant facilities."

[30] 2017 Infrastructure Report Card. Archived.

[31] Brücken: Zahlen, Daten, Fakten. 2019-06-24. Archived.

[32] Infrastruktura silniční dopravy v ČR a kraji k 1. 1. 2016. 2016-01-01. Archived.

[33] Lista de plazas de toros. Retrieved 2024-02-13. Archived.

[34] Is it Worth a Dam?. 1997. Retrieved 2013-05-20. Archived. "Worldwide, some 40,000 "large" dams (over 15 m high, according to the International Commission on Large Dams) and about 800,000 smaller ones have been constructed."

[35] Ranking Web of World Hospitals. 2015. Retrieved 2015-02-24. Archived. "The new edition is built from data collected in January 2015 for more than 16,500 Hospitals websites from all over the World."

[36] Total number of hospitals globally from 2021 to 2026. 2026. Retrieved 2026-06-08. Archived. "By 2026, the number of hospitals worldwide is projected to reach 215,977."

[37] Number of hotels and other accommodation establishments. Data by Countries from 1995 to 2024. Retrieved 2026-06-10. Archived. "Total: 817,196. Countries: 188."

[38] How many hotels in the world are there anyway? Booking.com keeps adding them. 2013-05-22. Retrieved 2013-05-22. Archived. "Booking.com says it offers 202,842 hotels globally. STR Global estimates that there are 187,000 hotels, offering 17.5 million guest rooms, around the globe. Other less-than-scientific guesstimates put the number of hotels around the world at around 400,000, with an additional 100,000 or so if you include B&Bs and hostels etc. In a similar vein, one of the global distribution systems informally uses 500,000 as a guide to the number of hotels in the world, although this number would exclude hostels, guest houses and motels."

[39] The Lighthouse Directory. Archived. "Welcome to the Lighthouse Directory, providing information and links for more than 24,400 of the world's lighthouses."

[40] List of cathedrals in Wikidata.

[41] Catholicism: How many physical Catholic churches are there in the world?. Archived.

[42] How many churches are there in the world?. Archived.

[43] Fun Fact: There are more churches (450,000) in the USA than there are convenience stores (146,341), fast food restaurants (160,000), and hotels/motels (46,295, not counting casino hotels) combined (352,636 total).. Archived.

[44] How Many Mosques Are There in the World?. Retrieved 2014-08-06. Archived.

[45] How many Mosques are there in the world?. Retrieved 2014-08-06. Archived.

[46] Global Integrated Power Tracker. Retrieved 2026-06-10. Archived. "200 country/areas included, 22,296 gigawatts of capacity covered, 182,400 power facilities tracked, 8,000+ facility owners."

[47] US has more prisoners, prisons than any other country. 2012-10-15. Archived.

[48] Global REservoir Inventory (GREI). 2025-01-08. Retrieved 2026-06-08. Archived. "GREI documents 556,063 reservoirs across six continents of the world, with a total water surface area of 469,497.10 km² and net water storage capacity of 7,563.04 ± 752.65 km³ (excluding human-regulated lakes with a total capacity of 626.80 km3). GREI includes a significant number of small reservoirs (herein classified as <1 km²) that are underreported in existing global reservoir datasets. Specifically, GREI compiles 39 times more small reservoirs than the recently released and widely used GeoDAR v1.1 dataset. Small reservoirs dominate the global distribution in count (95.38%) but contribute only 4.73% to total storage capacity. In contrast, medium-sized (1–10 km2) and large (≥10 km2) reservoirs account for only 3.84% and 0.78% by count but represent 8.62% and 86.65% of the global net capacity, respectively."

[49] SkyscraperPage.com. 2013-05-20. Retrieved 2013-05-20. Archived. "93,962 Structures (2013), 89,160 Structures (2012), 72,609 Structures (2010)."

[worldstadiums-50] Stadiums in the United States. 2013-05-20. Retrieved 2013-05-20. Archived.

[51] Ranking Web of World Universities. Archived.

[52] Zoos by Country 2024. Retrieved 2024-02-13. Archived. "The American Zoo and Aquarium Association (AZA) reports a staggering 10,000 zoos worldwide, reflecting the global popularity of these wildlife sanctuaries."

[imdbstats-53] 52.0 ^52.1 ^52.2 IMDb Database Statistics. Retrieved 2026-06-09. Archived. "Titles: 28,120,305; Names: 15,211,214."

[fccstats-54] 53.0 ^53.1 How Many TV and Radio Stations are There?. 2011. Retrieved 2013-05-21. Archived. "As on March 2011: 14,728 full power radio stations: 4,778 AM, 6533 FM, and 3,417 educational FM. There are 859 Low Power FM stations. 1,774 full power TV stations: 1,022 UHF commercial, 360 VHF commercial, 285 UHF educational, and 107 VHF educational. 10,595 translators and booster stations. 2,172 low power TV stations."

[indianmedia-55] 54.0 ^54.1 The wonder that is media. 2013-05-21. Retrieved 2013-05-21. Archived. "There are over 72,000 publications currently registered with the Registrar of Newspapers of India. At present, over 700 TV channels have been permitted by the Ministry of Information and Broadcasting to uplink or downlink from the country."

[56] Croissance du nombre de chaînes et de plates-formes de télévision européennes malgré la crise. 2010-01-13. Retrieved 2013-05-21. Archived. "Plus de 245 nouvelles chaînes de télévision ont été lancées en Europe en 2009 ; ce qui mène à la fin de l’année 2009 à un total de 7 200 chaînes de télévision européennes."

[57] How many radio stations are there in the world?. 2013-05-21. Retrieved 2013-05-21. Archived. "There are about 44,000 radio stations worldwide."

[58] Mapping the global landscape of journals. Retrieved 2026-06-13. Archived. "Our preliminary dataset is aggregated from five local and global information sources including a total of 152,644 unique journals matched with bibliographic metadata records from the International ISSN Centre."

[50Mjournalarticles-59] Article 50 million: An estimate of the number of scholarly articles in existence. Archived.

[60] ScienceOpen. Retrieved 2024-02-12. Archived. "91 million publications, 25,000 journals, 32 million authors."

[61] Europe PubMed Central. Retrieved 2026-06-08. Archived. "Research articles (48,250,198)."

[62] Scholia Statistics. Archived.

[63] Internet Archive Scholar. Retrieved 2024-02-12. Archived. "This fulltext search index includes over 35 million research articles and other scholarly documents preserved in the Internet Archive. The collection spans from digitized copies of eighteenth century journals through the latest Open Access conference proceedings and preprints crawled from the World Wide Web."

[64] IET Inspec. Retrieved 2026-06-08. Archived. "It contains over 27 million records of research literature from hundreds of trusted global publishers."

[65] PubMed Central. Retrieved 2026-06-08. Archived. "12.1 million articles are archived in PMC."

[66] Compendex on Engineering Village. Retrieved 2026-06-08. Archived. "10.3M+ papers from 150,000+ conference proceedings."

[67] About IEEE Xplore. Retrieved 2024-02-12. Archived. "IEEE Xplore contains more than 6 million documents and other materials from some of the world's most cited publications in electrical engineering, computer science, and related sciences. The content in IEEE Xplore comprises: Over 1.5 million research articles, Over 4 million conference papers, Over 14,000 technical standards, Over 66,000 books and book chapters, Over 500 online educational courses. Approximately 25,000 new content items are added to IEEE Xplore each month."

[68] rXiv.org. Retrieved 2024-02-12. Archived. "arXiv is a free distribution service and an open-access archive for nearly 2.4 million scholarly articles in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics."

[69] Open Access Theses and Dissertations. Retrieved 2026-06-08. Archived. "OATD.org aims to be the best possible resource for finding open access graduate theses and dissertations published around the world. Metadata (information about the theses) comes from over 1100 colleges, universities, and research institutions. OATD currently indexes 7,464,811 theses and dissertations."

[70] Grand Comics Database. Retrieved 2026-06-08. Archived. "Total: 2,189,540 issues."

[71] "Dictionary" search on Open Library.

[72] "Encyclopedia" search on Open Library.

[73] The ARTFL Encyclopédie

[74] Books of the world, stand up and be counted! All 129,864,880 of you. 2010-08-05. Retrieved 2010-08-05. Archived. "After we exclude serials, we can finally count all the books in the world. There are 129,864,880 of them. At least until Sunday."

[75] How Many Books Are In The World?. Archived.

[76] Incunabula Short Title Catalogue. 2013-05-21. Retrieved 2013-05-21. Archived. "The database records nearly every item printed from movable type before 1501, but not material printed entirely from woodblocks or engraved plates. 29,777 editions are listed as at January 8th 2008, including some 16th-century items previously assigned incorrectly to the 15th century."

[77] Universal Short Title Catalogue. Archived.

[chinaorgcnmassmedia-78] 77.0 ^77.1 Mass Media. Archived.

[79] MusicBrainz - Database statistics. Retrieved 2026-06-12. Archived. "Releases: 5,562,960."

[Discogs_releases-80] Discogs - search. Retrieved 2015-11-04. Archived.

[newusalbums-81] Business Matters: 75,000 Albums Released In U.S. In 2010 — Down 22% From 2009. 2011-02-18. Archived.

[82] El arte rupestre mundial y el arte rupestre como Patrimonio de la Humanidad. Retrieved 2026-07-06. Archived. "To date, some 100,000 prehistoric works of art have been found and registered, including objects. Most of these examples of rock art are distributed among 700,000 sites around the world, with paintings and engravings that contain some 20 million images. To date, 99% of the prehistoric art discovered is rock art."

[BBC_your_paintings-83] BBC - Your Paintings. Retrieved 2015-11-04. Archived.

[84] Le incisioni rupestri... segni del pensiero. Retrieved 2026-07-07. Archived. "The global census carried out by different research groups estimates that over 300,000 rock engravings are currently known. Thanks to continuous discoveries, this number is expected to increase progressively."

[85] United Nations Member States. Archived.

[86] Caves of the world. 2013-05-26. Retrieved 2013-05-26. Archived. "Number of caves = 2424; Caves deeper than 300m = 1075; Caves longer than 3kms = 1628."

[87] Mapping the World’s Glaciers. Archived.

[88] Kyrgyzstan Glaciers. Archived. "Glaciers, (8000 of them – one source says 8208), and permanent snow cover some 8100 square kilometers - about 30% of the total land area of the Kyrgyz Republic. The glaciers themselves cover about 4% of the surface area of the country."

[89] How many Alaska glaciers? No easy answer. Retrieved 2014-07-27. Archived. "Not long ago, a glaciologist wrote that the number of glaciers in Alaska "is estimated at (greater than) 100,000." That fuzzy number, perhaps written in passive voice for a reason, might be correct. But it depends upon how you count."

[90] Alaska's Glaciers. Archived. "745 Feature records have been selected from GNIS."

[91] Earth's many new lakes. Retrieved 2026-06-11. Archived. "The number of lakes on our planet has increased substantially in recent decades, according to a unique global survey of 3.4 million lakes. There has been a particular increase in the number of small lakes, which unfortunately, emit large amounts of greenhouse gas. The development is of great importance for Earth's carbon account, global ecosystems, and human access to water resources."

[belaruswater-92] Belarus Overview. Archived. "There are more than 20,000 rivers and creeks and about 11,000 lakes in Belarus."

[93] The Atlas of Canada. Archived. "31,752+larger than 3 km² (2-3 million in total)."

[94] Which country has the most lakes?. Archived.

[95] Lakes in Finland. Archived. "There are 187,888 lakes in Finland. Lake is here defined as a body of standing water larger than 5 ares (500 m2). 56,000 over 10,000 m²."

[96] Data available for 150,000, only 75,000 with name, 57,000 in sv:Kategori:Listor över Sveriges insjöar.

[97] Mountains Mount. 2012-05-30. Retrieved 2013-05-26. Archived.

[98] HydroRIVERS. Retrieved 2026-06-11. Archived. "The global coverage of HydroRIVERS encompasses 8.5 million individual river reaches with an average length of 4.2 km, representing a total of 35.9 million km of rivers globally."

[99] Cartographic river drainage databases. Archived.

[100] More than half of Europe's rivers fail ecological targets, report finds. Archived.

[101] According to unknown sources there are 8,188 rivers less than 25 km, only 24 rivers over 100 km.

[102] National Aquaculture Sector Overview - Brazil. Archived.

[103] China - Geography and population. Archived.

[104] 28,000 Rivers Disappeared in China: What Happened?. Archived.

[105] El Salvador - Physical Features. Archived.

[106] HYDRO ENERGY. Archived.

[107] Hydropower, indigenous peoples’ rights and popular resistance in Guatemala. Archived.

[108] Water and hydropower Resources of the Kyrgyz Republic. Archived.

[109] Воды. Archived. "2,044 over 10 km."

[110] Nepal River Conservation Trust. Archived. "The latest data shows that Nepal has got over 6000 rivers and streams which have got hydropower potential."

[111] Panama - Geography. Archived. "Nearly 500 rivers lace Panama's rugged landscape. Mostly unnavigable, many originate as swift highland streams, meander in valleys, and form coastal deltas."

[112] Inland fisheries of Europe. Archived. "In addition to the dominating Danube, Romania has over 4,000 rivers having watersheds larger than 10 km2 and a total length exceeding 60,000 km."

[113] Russia:: Rivers and Lakes. Archived. "Among its 100,000 rivers, Russia contains some of the world's longest. Four of the country's five longest rivers—the Ob-Irtysh, Amur, Lena, and Yenisey—are in Siberia."

[114] Russia - Water report. Archived. "There are 120,000 rivers over 10 km long. Their total length within the Russian Federation equals 2.3 million km."

[115] Spain - Rivers. Archived. "Of the roughly 1,800 rivers and streams in Spain, only the Tagus is more than 960 kilometers long; all but 90 extend less than 96 kilometers."

[116] FAO Fishery Country Profile - UKRAINE. Archived. "Ukraine has about 71,000 rivers, with a total length of 248,000 km. Among them, 3,212 rivers have a length of more than 10 km and total 73,700 km in length."

[117] River Facts. Archived.

[118] Wikipedia talk:WikiProject Rivers. Archived. "2,000,000+ including small streams."

[119] Venezuela - Rivers. Archived. "The Orinoco is by far the most important of the more than 1,000 rivers in the country."

[120] How many volcanoes are there in the world?. Archived.

[121] EventKG - A Multilingual Event-Centric Temporal Knowledge Graph. Retrieved 2026-06-20. Archived. "The EventKG is a multilingual resource incorporating event-centric information extracted from several large-scale knowledge graphs such as Wikidata, DBpedia and YAGO, as well as less structured sources such as the Wikipedia Current Events Portal and Wikipedia event lists in 15 languages. EventKG provides information for over 1.3 million events and over 4.5 million temporal relations."

[122] Censo-Guía de Archivos de España e Iberoamérica. Archived.

[ukglam-123] 122.0 ^122.1 ^122.2 Libraries, Archives, Museums and Publishing Online Statistics Tables. Archived.

[124] OCLC President’s Report. Archived.

[125] Burundi - Libraries and museums. Archived. "There are 60 public libraries in Burundi, with the largest in and around the capital. Libraries in Bujumbura include the Public Library, which has 27,000 volumes; the library of the University of Burundi, with 192,000 volumes; and a specialized collection at the Department of Geology and Mines. The French Cultural Center in Bujumbura holds 33,000 volumes."

[126] How many libraries are in Canada?. Archived.

[127] Croatia - Libraries and museums. Archived. "In 1995, the country reported having 232 public libraries with a combined collection of 4.6 million volumes."

[128] Cuba cuenta con más de 400 bibliotecas públicas en todo el territorio nacional, incluidas las situadas en las montañas. Archived.

[129] Czech Republic - Libraries and museums. Archived. "In 1997, the Czech Republic had 6,245 public libraries with 53.7 million volumes and 1.4 million registered users."

[130] Denmark - Libraries and museums. Archived. "As of 2002, there were 250 free public libraries throughout the country with 892 points of service. That year, the public libraries had a total of more than 31.4 million volumes."

[131] Finland - Libraries and museums. Archived. "There are about 400 research and university libraries in Finland, most of which are small. In 1997 there were 436 central public libraries and 1,202 branch libraries."

[finlandcordis-132] 131.0 ^131.1 Report on the situation of libraries, museums and archive. Archived. "In Finland there were 439 public libraries having 1006 branches and 370 research libraries with 465 branches in 1996. The total number of library units was 1471. The total number of museums in Finland is 280, of which 139 are cultural history museums, 71 special museums, 55 art museums and 17 natural history museums."

[francenations-133] 132.0 ^132.1 France - Libraries and museums. Archived. "In 1997 there were 1,620 central public libraries with a combined total of more than 89.8 million volumes. There are more than 1,000 museums in France."

[134] FYI France. Archived.

[germanynations-135] 134.0 ^134.1 Germany - Libraries and museums. Archived. "As of 1997, Germany had 6,313 public libraries with 149 million volumes in total. Germany has more than 4,500 state, municipal, association, private, residential, castle, palace, and church and cathedral treasures museums, which annually attract over 100 million visitors."

[136] Greece - Libraries and museums. Archived. "In 1997, there were 672 public libraries with a total of 9.1 million volumes."

[hungarynations-137] 136.0 ^136.1 Hungary - Libraries and museums. Archived. "As of 1997, there were 3,518 regional public libraries located throughout the country. There were over 500 museums (about 70 in Budapest) and many zoological and botanical gardens."

[icelandnations-138] 137.0 ^137.1 Iceland - Libraries and museums. Archived. "There were a total of 187 public libraries with combined holdings of 1.9 million volumes in 1997. Iceland has more than 50 museums."

[139] Latvia - Libraries and museums. Archived. "In 1997, the country counted 998 public libraries housing 14.9 million volumes."

[140] Lithuania - Libraries and museums. Archived. "In 1997, there were 1,478 public libraries in the country."

[morocconations-141] 140.0 ^140.1 Morocco - Libraries and museums. Archived. "Of the 18 public libraries in Morocco, the largest is in Casablanca, with almost 360,000 volumes."

[142] Netherlands - Libraries and museums. Archived. "In 1997 there were 579 main public libraries with a combined collection of 41.5 million books."

[143] Korea, Democratic People's Republic of (DPRK) - Libraries and museums. Archived. "The DPRK has more than 200 public libraries, the largest being the Grand People's Study House in P'yongyang, with 20 million volumes."

[144] Norway - Libraries and museums. Archived. "Norway's 1,108 public libraries had 20.5 million volumes in 1997."

[145] Panama - Libraries and museums. Archived. "There are more than 40 other public libraries and branches."

[perunations-146] 145.0 ^145.1 Peru - Libraries and museums. Archived. "There are nearly 200 public libraries in Peru, the largest of them in Callao, Arequipa, and Lima. More than 250 public and private museums."

[polandnations-147] 146.0 ^146.1 Poland - Libraries and museums. Archived. "In 1997 there were 9,230 public libraries, jointly holding almost 135 million volumes. Of the more than 500 museums in Poland..."

[portugalnations-148] 147.0 ^147.1 Portugal - Libraries and museums. Archived. "In 1997 the country had 168 public libraries with 4.8 million volumes. There are some 300 museums in Portugal."

[romanianations-149] 148.0 ^148.1 Romania - Libraries and museums. Archived. "In 1997, the country had over 2,950 public libraries holding a total collection of 50.5 million volumes. Romania has some 400 museums."

[russianations-150] 149.0 ^149.1 Russia - Libraries and museums. Archived. "In 1995, the country counted 50,032 public libraries, holding in total 983.4 million volumes. Russia has over 1,000 museums."

[swedennations-151] 150.0 ^150.1 Sweden - Libraries and museums. Archived. "In 1997, Sweden had 324 public libraries. Sweden has about 200 museums."

[152] Tanzania - Libraries and museums. Archived. "The Tanzania Library Service was established in 1964. It maintains the National Central Library in Dar es Salaam (656,000 volumes), 16 public libraries, school library service, and a rural extension service."

[153] Tunisia - Libraries and museums. Archived. "The collections of Tunisia's approximately 250 public libraries hold over 2.7 million volumes."

[154] Ukraine - Libraries and museums. Archived. "In 1995, there were reported to be 21,857 public libraries operating in Ukraine with an overall stock of 336.7 million books."

[155] Library Copyright Alliance. Archived.

[156] Zimbabwe - Libraries and museums. Archived. "There were more than 150,000 registered public library users using 76 public libraries holding 1.1 million volumes in 1989. In 1990, 100,000 people visited Zimbabwe's 11 museums."

[157] Books, manuscripts, journals, newspapers, magazines, sound and music recordings, videos, play-scripts, patents, databases, maps, stamps, prints, drawings. 14 million are books, 3 million recordings. See also British Library Sound Archive.

[158] About the Smithsonian. Archived.

[159] Carl Malamud Answers: Goading the Government To Make Public Data Public. Archived.

[160] Museums worldwide - statistics & facts. Archived. "According to the latest estimates by UNESCO, there were nearly 104,000 such organizations globally, with the regions of North America and Western Europe reporting the highest number of museums worldwide."

[161] Frequently Asked Questions. Archived.

[162] The Cost of Digitising Europe's Cultural Heritage. Archived. "there are approximately 17,673 museums in Europe, based on figures submitted between 2003 and 2008."

[163] Arts and Culture in Australia: A Statistical Overview, 2010. Archived. "According to Museums, Australia, 2007-08 (cat. no. 8560.0) there were 1,019 museums operating from 1,276 locations in Australia at the end of June 2008. These locations included 768 social history museums, 425 historic properties and sites, and 83 other museums."

[164] Interesting Facts About Canadian Museums. Archived. "Canada has more than 2,400 museums, which have more than 24,000 paid employees and 55,000 volunteers, and receive nearly 54 million visits annually."

[165] Museums in Germany – where history and culture are brought to life. Archived. "The 4,000 or so museums in Germany serve as worlds of discovery and use exciting concepts to explore art and history, technology and architecture, literature and the natural world."

[166] How many museums in Pakistan?. Archived.

[167] Visit museums in Spain. Archived.

[168] Frequently asked questions. Archived. "It is estimated that there are about 2,500 museums in the UK, depending on what you include. Over 1,800 museums have been accredited by the Museums, Libraries and Archives Council (MLA)."

[169] How many museums are there in the United States?. Archived.

[170] Atlas database. Archived.

[171] Natural history museums around the globe contain over 1.1 billion objects. Retrieved 2026-06-13. Archived. "They have looked at the collections held in 73 museums found in 28 countries and discovered that collectively these institutions hold some 1,147,934,687 objects."

[172] Webaldic. Retrieved 2026-06-21. Archived. "With over 6 million coats of arms, indexed and searchable in one database, Webaldic helps you uncover the identity and meaning of coats of arms."

[173] Flags of the World. Retrieved 2026-06-21. Archived. "Flags of the World (FOTW), founded in 1994, is the Internet’s largest site devoted to vexillology (the study of flags). Here you can read more than 90,000 pages about flags and view more than 223,000 images of flags of countries, organizations, states, territories, districts and cities, both past and present."

[174] Gigantes. Retrieved 2026-06-13. Archived. "Gigantes is the most extensive and realistic void catalog suite ever released, containing over 1 billion cosmic voids covering a volume larger than the observable universe, more than 20 TB of data, and created by running the void finder VIDE on the halos from the Quijote simulations. Gigantes provides the tools for intensive machine learning exploration of void statistics."

[numberofgalaxies-175] 174.0 ^174.1 Astronomers were wrong about the number of galaxies in universe. 2021-01-14. Archived.

[numberofgalaxies2-176] 175.0 ^175.1 How many galaxies are in the universe? A lot more than you'd think. 2023-07-25. Archived.

[177] Researchers launch REGALADE: The most complete galaxy catalogue for modern astronomy. Retrieved 2026-06-11. Archived. "An international team of scientists has introduced REGALADE (Revised Galaxy List for the Advanced Detector Era), an unprecedented all-sky catalogue that brings together nearly 80 million galaxies."

[178] Euclid Telescope Discerns 26 Million Galaxies in New Update of Sky Map. Retrieved 2026-06-11. Archived. "With one scan of each deep field, Euclid has been able to spot 26 million galaxies, the farthest of which lie 10.5 billion light-years away. To classify this deluge of cosmic data, the ESA has called upon citizen scientists to help classify the galaxies with some assistance from AI algorithms. More than 380,000 galaxies have been classified so far, but this amount is just one drop of a colossal data pool that will bring images of 1.5 billion galaxies to light over the next few years."

[gaia-179] 178.0 ^178.1 Gaia Archive. Archived.

[nasajpl-180] 179.0 ^179.1 ^179.2 JPL Solar System Dynamics. Archived.

[181] How Many Species Are There on Earth and in the Ocean?. Archived.

[Book-Biology-182] The Biology of Rarity: Causes and consequences of rare—common differences. Retrieved 2015-05-26. Archived.

[StearnsStearns2000-183] Watching, from the Edge of Extinction. Retrieved 2017-05-30. Archived.

[NYT-20141108-MJN-184] Prehistory’s Brilliant Future. 2014-11-08. Retrieved 2014-12-25. Archived.

[Newman-185] Newman, Mark. A model of mass extinction. 1997. Journal of Theoretical Biology 189: 235–252.

[186] UniProtKB statistics. Retrieved 2026-06-10. Archived. "Number of entries in total: 149,810,139."

[187] Expanding and Enriching the LncRNA Gene–Disease Landscape Using the GeneCaRNA Database. Retrieved 2026-06-11. Archived. "The GeneCaRNA human gene database is a member of the GeneCards Suite. It presents 280,000 human non-coding RNA genes, identified algorithmically from 690,000 RNAcentral transcripts. This expands by tenfold the ncRNA gene count relative to other sources. GeneCaRNA thus contains ~120,000 long non-coding RNAs (LncRNAs, >200 bases long), including 100,000 novel genes."

[188] CAS REGISTRY. Retrieved 2026-06-12. Archived. "CAS REGISTRY is a database of disclosed chemical substances curated from scientific literature and other sources. It contains over 290 million substances and is continuously enhanced with new substances."

[189] PubChem Data Counts. Retrieved 2026-06-12. Archived. "Compounds: 123,914,913. Unique chemical structures extracted from contributed PubChem Substance records."

[190] How Many Chemical Compounds Are There?. Retrieved 2026-06-12. Archived. "The number of chemical substances formally documented and registered stands at an astonishing scale. The primary global registry identifies over 290 million unique substances, a figure that grows by approximately 15,000 new substances every day, reflecting rapid global research and discovery. Much of this growth comes from organic chemistry, involving carbon-based molecules, and the complex field of biopolymers."

[191] CAS REACTIONS. Retrieved 2026-06-12. Archived. "The CAS reactions collection provides detailed and dependable data on more than 150 million single and multi-step reactions."

[192] Cambridge Structural Database (CSD). Retrieved 2026-06-12. Archived. "Established in 1965 with historical structures dating back to the 1920s, the Cambridge Structural Database (CSD) is the world’s largest curated repository of experimental crystal structures. It contains over 1.4 million accurate 3D structures derived from X-ray, neutron, and electron diffraction analyses. The database is used by researchers across the pharmaceutical, agrochemical, and fine chemicals industries to predict and guide future discoveries."

[193] Particle Data Group. Retrieved 2026-06-12. Archived.

[194] The On-Line Encyclopedia of Integer Sequences (OEIS). Retrieved 2026-06-13. Archived. "Contains 396,547 sequences."

[195] ClinicalTrials.gov. Retrieved 2026-06-12. Archived. "ClinicalTrials.gov is a place to learn about 589,453 studies with locations in all 50 states and in 226 countries and territories."

[196] Measuring Diagnoses: ICD Code Accuracy. Archived.

[197] How many drug targets are there?. Archived. "1,357 unique drugs: 1,204 are 'small-molecule drugs' and 166 are 'biological' drugs."

[198] Biographies by gender in Wikidata.

[worldometers-199] Worldometers - real time world statistics. Archived.

[200] How Many People Have Ever Lived on Earth?. Archived.

[201] Occupations in Wikidata.

[forebears-202] 201.0 ^201.1 About Forebears Names. Retrieved 2026-06-12. Archived. "Forebears Names is a free service providing access to the largest geospatial database of forename and surname distribution and demographics. It provides the approximate incidence of forenames and surnames produced from a database of 4,044,546,938 people (55.5% of living people in 2014). As of September 2019 it covers 27,662,801 forenames and 27,206,821 surnames in 236 jurisdictions."

[203] Unicode Version 17.0 Character Counts. Retrieved 2026-06-21. Archived. "Total Assigned: 297,334."

[204] How Many Companies Are There? NEW 2025 Statistics. Retrieved 2026-06-12. Archived. "There are around 359 million companies worldwide. There are 33.2 million businesses in the US. Small businesses make up 90% of all businesses globally. Approximately 100 million new businesses start each year worldwide."

[205] India: More NGOs, than schools and health centres. 2010-07-07. Retrieved 2011-10-07. Archived.

[206] First official estimate: An NGO for every 400 people in India. 2010-07-07. Archived.

[207] Hobbled NGOs wary of Medvedev. 2008-05-07. Archived.

[208] Fact Sheet: Non-Governmental Organizations (NGOs) in the United States. Archived.

[209] Adherents.com. 2013-05-23. Retrieved 2013-05-24. Archived. "Adherents.com is a growing collection of over 43,870 adherent statistics and religious geography citations: references to published membership/adherent statistics and congregation statistics for over 4,200 religions, churches, denominations, religious bodies, faith groups, tribes, cultures, movements, ultimate concerns, etc."

[210] Let's Document all the File Formats!. Retrieved 2026-06-13. Archived. "Statistics: 6,667 articles."

[211] Museum of Obsolete Media. Retrieved 2026-06-13. Archived. "A unique online museum of physical media formats showcasing developments in audio, video, film and data storage."

[212] Viruses Expected to Hit 1 Million This Year. 2008-04-06. Archived.

[25Billion-213] App Store's 25 Billionth Download Comes From China with 'Where's My Water? Free'. Archived.

[Google_Play_About_To_Pass_15_Billion_App_Downloads-214] Google Play About To Pass 15 Billion App Downloads? Pssht! It Did That Weeks Ago. 2012-05-07. Retrieved 2012-05-22. Archived.

[215] Global Aviation Statistics. Retrieved 2026-06-10. Archived. "84,330 airports, 179,932 flight routes, 249 countries, 1,431 airlines."

[216] rsetti/airportsdata. Retrieved 2026-06-10. Archived. "Extensive database of current data for nearly every airport and landing strip in the world, with over 28,000 entries."

[217] The Global Airport Database. Retrieved 2026-06-10. Archived. "The Global Airport Database (GADB) is a free downloadable database of 9,300 airports big and small from all around the world."

[218] Ports Directory. Retrieved 2026-06-09. Archived. "This directory covers 20,559 ports across 236 countries and territories, each identified by its UN/LOCODE."

[219] World Port Directory. Retrieved 2026-06-09. Archived. "19,445 ports — Search by name, country or UN/LOCODE."

[220] The World Factbook — COUNTRY COMPARISON :: ROADWAYS. Archived.

[221] SIC 1622: BRIDGE, TUNNEL, AND ELEVATED HIGHWAY CONSTRUCTION. Archived. "Of the more than 600,000 bridges in the United States, 45 percent are under the financial jurisdiction of state governments, and 38 percent are controlled by county authorities."

[dbrepenwiki-222] 221.0 ^221.1 ^221.2 Wikipedia:Database reports/Page count by namespace.

[dbrepcommons-223] 222.0 ^222.1 ^222.2 Commons:Database reports/Page count by namespace.

[224] Category:Disambiguation pages.

[225] Wikipedia:Contents/Portals.

[226] About GeoNames. Retrieved 2026-06-15. Archived. "The GeoNames geographical database is available for download free of charge under a creative commons attribution license. It contains over 25 million geographical names and consists of over 12 million unique features whereof 4.8 million populated places and 16 million alternate names."

[227] Alien Life Imagined: Communicating the Science and Culture of Astrobiology. Archived.

[228] Atoms in the Universe. Archived.

[229] 52nd Known Mersenne Prime Discovered. Archived.

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