and Face to 8,320 m (27,300 ft) using oxygen. On June 7, George Mallory led a third attempt but set off an avalanche, killing seven Sherpa climbers- the first reported deaths on Everest. 1924: Mallory and Irvine George Mallory, right, and Andrew Irvine . Photo source: http://bit.ly/mfnTtl The third British expedition