In 1852, the Great Trigonometric Survey of India determined that Mount Everest, until then an obscure Himalayan peak, had been definitively identified as the world's highest mountain. This announcement captured the international imagination, and soon the idea of reaching the summit of the "roof of the world" was viewed as the ultimate geographic feat. Attempts to climb Everest, however, could not begin until 1921, when the forbidden kingdom of Tibet first opened its borders to outsiders.

On June 8, 1924, two members of a British expedition, George Mallory and Andrew Irvine, attempted the summit. Famous for his retort to the press—"because it's there"—when asked why he wanted to climb Everest, Mallory had already failed twice at reaching the summit. The two men were last spotted "going strong" for the top until the clouds perpetually swirling around Everest engulfed them. They then vanished.

Mallory's body was not found for another 75 years, in May 1999. No evidence was found on his body—such as a camera containing photos of the summit, or a diary entry recording their time of arrival at the summit—to clear up the mystery of whether these two Everest pioneers made it to the top before the mountain killed them.

Ten more expeditions over a period of thirty years failed to conquer Everest, with 13 losing their lives. Then, on May 29, 1953, Edmund Hillary, a New Zealand beekeeper, and Tenzing Norgay, an acclaimed Sherpa climber, became the first to reach the roof of the world. Their climb was made from the Nepalese side, which had eased its restrictions on foreigners at about the same time that Tibet, invaded in 1950 by China, shut its borders.

World famous overnight, Hillary became a hero of the British empire—the news reached London just in time for Elizabeth II's coronation—and Tenzing was touted as a symbol of national pride by three separate nations: Nepal, Tibet, and India.

Although not considered one of the most technically challenging mountains to climb (K2, the world's second highest mountain, is far more difficult), the dangers of Everest include avalanches, crevasses, ferocious winds up to 125 mph, sudden storms, temperatures of 40°F below zero, and oxygen deprivation. In the "death zone"—above 25,000 feet—the air holds only a third as much oxygen as at sea level, heightening the chances of hypothermia, frostbite, high-altitude pulmonary edema (lungs fatally fill with fluid) and high-altitude cerebral edema (oxygen-starved brain swells up).

Even when breathing bottled oxygen, climbers experience extreme fatigue, impaired judgment and coordination, headaches, nausea, double vision, and sometimes hallucinations. Expeditions spend months acclimatizing and usually attempt Everest only in May and October, avoiding the winter snows and the summer monsoons.

After Hillary and Tenzing's ascent of Everest, other records were broken, including the first ascent by a woman, the first solo ascent, the first to traverse up one route and down another, and the first descent on skis.

Yet none of these records compared to the next true milestone: climbing Everest without supplemental oxygen. As far back as Mallory, who called the use of bottled oxygen "unsporting," climbers found they had no alternative.

But on May 8, 1978, two Tyrolean mountaineers, Reinhold Messner and Peter Habeler, achieved the impossible. Messner had resolved that nothing would come between him and the mountain; he would climb Everest without supplemental oxygen or not at all. At the summit he described himself as "nothing more than a single narrow gasping lung."

Incredulous, some disputed the veracity of a climb without supplemental oxygen. Yet two years later, Messner quashed all skepticism when on August 20, 1980, he again ascended Everest without oxygen, this time solo (another Everest first). Climbing without oxygen has now become de rigueur among the climbing elite, and by 1996 more than 60 men and women had reached the top relying on their own gasping lungs.

From 1921—2009, Everest has been climbed by more than 4,500 people from over eighty nations. More than 200 have lost their lives, making the odds on not coming down alive about one in twenty-one.

The dead are left where they perish because the effects of altitude make it nearly impossible to drag bodies off the mountain. Those ascending Everest pass through an icy graveyard littered with remnants of old tents and equipment, empty oxygen canisters, and frozen corpses.

In the past few years, media access to Everest has mushroomed: live Internet reports have been sent from the mountain (using solar energy); an Imax film crew has documented a climb; and Jon Krakauer's bestselling account about an Everest ascent gone wrong, Into Thin Air, has introduced cwm, col, sirdar, short-rope, and Hillary Step into the vocabulary of mainstream America.

One reason for the recent media attention is the novelty of comparatively ordinary people venturing up a Mount Olympus formerly limited to mountaineering gods like Messner and Hillary. There are now guided trips up the mountain, fanning debate about the commercialization of Everest. Pathologists and postal workers can now follow in the footsteps of the greatest mountaineers. Purists like Hillary lament the lack of respect for the mountain, and young Turks boast they can get nearly anyone up the mountain as long as they're in decent physical shape and have $65,000 to spare.

Another reason for so much media attention is the appalling waste of human life. In May 1996, eight lost their lives in the single greatest disaster on the mountain—yet it did not stop others from attempting the climb just weeks later, resulting in four more deaths. The total for the year was fifteen. As the number of climbers grow, so does the death toll, with Everest taking down world-class climbers and novice adventurers alike.

With so many ambitious climbers determined to scale Everest, their ethics and single-minded pursuit of personal glory have come under criticism. In 2006, more than 40 climbers were believed to have passed by a dying British climber on their way to the summit—none came to his aid. It is true that helping a gravely ill or injured climber while in Everest's death zone could very well jeopardize one's own life. It is also true that it is grossly unfair when climbers have had to sacrifice their own dreams of climbing Everest in order to rescue irresponsible and poorly prepared individuals who never should have been on the mountain in the first place. But one wonders how such a climber sleeps at night, knowing he left another to die, whatever the reason. As Hillary remarked about the incident, "I think the whole attitude towards climbing Mount Everest has become rather horrifying. The people just want to get to the top. They don't give a damn for anybody else who may be in distress."