Timeline of climbing Mount Everest

Mount Everest is the world's highest mountain, with a peak at 8,848 metres (29,029 ft) above sea level. It is situated in the Himalayan range in Tibet.

The first British expedition – organized and financed by the newly formed Mount Everest Committee – came under the leadership of Colonel Charles Howard-Bury, with Harold Raeburn as mountaineering leader, and included George Mallory, Guy Bullock and Edward Oliver Wheeler. It was primarily for mapping and reconnaissance to discover whether a route to the summit could be found from the north side. As the health of Raeburn broke down, Mallory assumed responsibility for most of the exploration to the north and east of the mountain. He wrote to his wife: "We are about to walk off the map..." After five months of arduous climbing around the base of the mountain, Wheeler explored the hidden East Rongbuk Glacier and its route to the base of the North Col. On September 23, Mallory became the first person to set foot on the mountain and he, Bullock and Wheeler reached the North Col at 7,020 metres (23,030 ft) before being forced back due to strong winds. To Mallory's experienced eye, the route up the North ridge intersecting the NE Ridge and from there to the summit looked long, but feasible for a fresher party.

The second British expedition, under General Charles Granville Bruce and climbing leader Lt-Col. Edward Lisle Strutt, and containing Mallory, returned for a full-scale attempt on the mountain. On May 22, they climbed to 8,170 m (26,800 ft) on the North Ridge before retreating. They were the first humans to climb above 8,000 metres (26,000 ft) on a mountain. The scope of this accomplishment is reflected by the fact that there are only 14 mountains on earth – the eight-thousanders – that reach and exceed 8,000 metres. At that moment, Mallory and Strutt had exceeded the summit of all but five other mountains on the planet.

A day later, George Finch and Geoffrey Bruce climbed up the North Ridge and Face to 8,320 m (27,300 ft) using oxygen for the first time. They climbed from the North Col to their highest camp at a phenomenal rate of 900 vert-ft/hr., and were the first climbers to sleep using oxygen.

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