linguistic:paraphrasing, information:classification
Early attempts

In 1885, Clinton Thomas Dent, president of the Alpine Club, suggested that climbing Mount Everest was possible in his book Above the Snow Line.

The northern approach to the mountain was discovered by George Mallory and Guy Bullock on the initial 1921 British Reconnaissance Expedition. It was an exploratory expedition not equipped for a serious attempt to climb the mountain. With Mallory leading (and thus becoming the first European to set foot on Everest's flanks) they climbed the North Col to an altitude of 7,005 metres (22,982 ft). From there, Mallory espied a route to the top, but the party was unprepared to climb any further and descended.

The British returned for a 1922 expedition. George Finch climbed using oxygen for the first time. He ascended at a remarkable speed— 290 metres (951 ft) per hour—and reached an altitude of 8,320 m (27,300 ft), the first time a human reported to climb higher than 8,000 m. Mallory and Col. Felix Norton made a second unsuccessful attempt.

The next expedition was in 1924. The initial attempt by Mallory and Geoffrey Bruce was aborted when weather conditions prevented the establishment of Camp VI. The next attempt was that of Norton and Somervell, who climbed without oxygen and in perfect weather, traversing the North Face into the Great Couloir. Norton managed to reach 8,550 m (28,050 ft), though he ascended only 30 m (98 ft) or so in the last hour. Mallory rustled up oxygen equipment for a last-ditch effort. He chose young Andrew Irvine as his partner.

On 8 June 1924, George Mallory and Andrew Irvine made an attempt on the summit via the North Col-North Ridge-Northeast Ridge route from which they never returned. On 1 May 1999, the Mallory and Irvine Research Expedition found Mallory's body on the North Face in a snow basin below and to the west of the traditional site of Camp VI. Controversy has raged in the mountaineering community whether one or both of them reached the summit 29 years before the confirmed ascent and safe descent of Everest by Sir Edmund Hillary and Tenzing Norgay in 1953.

In 1933, Lady Houston, a British millionairess, funded the Houston Everest Flight of 1933, which saw a formation of two aeroplanes led by the Marquess of Clydesdale fly over the Everest summit.

Early expeditions—such as Charles Bruce 's in the 1920s and Hugh Ruttledge 's two unsuccessful attempts in 1933 and 1936 —tried to ascend the mountain from Tibet, via the North Face. Access was closed from the north to Western expeditions in 1950 after China took control of Tibet. In 1950, Bill Tilman and a small party which included Charles Houston, Oscar Houston, and Betsy Cowles undertook an exploratory expedition to Everest through Nepal along the route which has now become the standard approach to Everest from the south.

The 1952 Swiss Mount Everest Expedition, led by Edouard Wyss-Dunant, was granted permission to attempt a climb from Nepal. It established a route through the Khumbu icefall and ascended to the South Col at an elevation of 7,986 m (26,201 ft). Raymond Lambert and Sherpa Tenzing Norgay were able to reach an elevation of about 8,595 m (28,199 ft) on the southeast ridge, setting a new climbing altitude record. Tenzing's experience was useful when he was hired to be part of the British expedition in 1953. The Swiss decided to make another post-monsoon attempt in the autumn; they made it to the South Col but were driven back by winter winds and severe cold.