Pictures: Climbing Everest Through History

The tragedy on Everest recalls the highs and lows of the long history of climbing the mountain.

First to reach the top of the world, Edmund Hillary and Tenzing Norgay were all smiles in Kathmandu, Nepal, where they posed in their climbing gear weeks after their famous ascent.

Edmund Hillary, a New Zealander, and Tenzing Norgay, a Nepalese Sherpa, were the strongest and most experienced snow and ice climbers on the 1953 British expedition.

After the first team was forced to turn back, Hillary and Tenzing, the back-up team, reached the top at 11:30 a.m. on May 29. To celebrate, Hillary offered a customary handshake, but Tenzing threw his arms around Hillary, and they thumped each other's backs in joy.

Still a long way from the snow-plumed South Summit, members of the 1963 American Mount Everest Expedition cross the dizzyingly steep slope of neighboring Lhotse at 25,000 feet. Accompanied by Nawang Gombu Sherpa, Jim Whittaker became the first American to reach the true summit on May 1 by the now familiar South Col route. Three weeks later Willi Unsoeld and Tom Hornbein ascended via the challenging West Ridge.

In preparation for "a little war against a big mountain," as expedition leader Norman G. Dyhrenfurth put it, an army of more than 900 porters in February 1963 crosses a log bridge single file on their 185-mile trek to Mount Everest. Carrying 27 tons of supplies on their backs in support of the first American attempt on the peak, the porters stretched for four miles along the trail.

Trekkers on the main trail to Mount Everest in 1979 pass stunningly beautiful Ama Dablam, which tops out at 22,493 feet (6,865 meters). The next stop on the trail: Tengboche Monastery, where most Sherpas and many mountaineers stop for a blessing from the high lama.

Jubilant to reach the 29,035-foot (8,850-meter) peak of Mount Everest, German climber Hubert Hillmaier waves a flag in the thin air on October 14, 1978. Part of a German-French expedition, Hillmaier ascended via the Southeast Ridge with fellow Germans Sepp Mack and Hans Engl. Engl made the climb without bottled oxygen, following the example of Italian Reinhold Messner and Austrian Peter Habeler, who were the first to do so, in May 1978.

Members of the Altitude Everest Expedition 2007 cross a snowfield en route to the north side of Mount Everest. Their goal was to retrace the path of British climber George Mallory, who disappeared high on the peak in 1924 with his partner Sandy Irvine. Conrad Anker, leader of the 2007 expedition, discovered Mallory's body at 27,000 feet on Everest in 1999. Irvine's body hasn't yet been found. The question of whether Mallory and Irvine reached the summit also remains a mystery.

A climber crosses a narrow ice bridge in the Khumbu Icefall in 2012. Often described as one of the most dangerous passages during a climb of the standard Southeast Ridge route, the icefall is a shifting jumble of house-size blocks of ice at the crumbling base of the Khumbu Glacier, not far from Everest base camp.