After several unsuccessful attempts to climb the mountain during the 1920s and 1930s, New Zealander Edmund Hillary and Sherpa Tenzing Norgay made it to the top in 1953, scaling the mountain from its southern approach. Between 1953 and today, Everest has been summited more than 13,700 times. However, more than 300 people have died on the mountain, with more than half perishing in avalanches or from falls or succumbing to altitude sickness (or acute mountain sickness)—a condition caused by the lack of oxygen in the body’s tissues.

Today, some 700 to 1,000 set out to climb Everest each year. Bare-bones, no-frills experiences cost $30,000–$70,000, depending on whether you climb Everest from the Nepali side or the Tibetan side. Others offering amenities (such as comfortable accommodations, premium guides, and priority climbing timeslots) can top out at $1,000,000 per climber. The April–May window (which follows the winter storms and precedes the onset of the Indian summer monsoon) is the most popular period to climb, with a smaller period of calm weather following in September.

Still, with so many people seeking to conquer the mountain each year, the mountain has developed a serious garbage problem. Waste—including cans, plastic containers, cast-off tents and camping equipment, oxygen canisters, and human excrement—builds up each year. Even though much of the waste is hauled from the higher base camps to pits near local villages below, monsoon rains wash some of it down the mountain, where it contributes to water pollution in glacial streams and other waterways.