The assault on Everest in 1924 followed a direct approach up the East Rongbuk Glacier to a basin of ice below the North Col from which the line followed the broad north ridge to the north-east ridge and from thence to the summit. Six camps were established: three along the East Rongbuk Glacier, one on the North Col at 23,000 feet, and two more at 25,000 and 27,000 feet.
This photograph is taken towards the end of the expedition, probably during Somervell and Norton's unsuccessful oxygen-less attempt on 4 June 1924 (Norton finally turned back at 28,126ft). Mallory and Irvine spent the day watching and waiting with Odell at Camp III before climbing to Camp IV on the North Col that evening, making a final test of the oxygen sets they would use on their gas-assisted attempt on the summit.
Odell took what would be the last photograph of Mallory and Irvine on 6 June 1924 as they prepared to leave Camp IV. On 8 June, whilst climbing at just over 26,000ft on the crest of the main north ridge, he witnessed through a clearing of the mist the last sighting of Mallory and Irvine making their way towards the summit: 'I noticed far away on a snow slope leading up to what seemed to me to be the last step but one from the base of the final pyramid, a tiny object moving and approaching the rock step. A second object followed, and then the first climbed to the top of the step. As I stood intently watching this dramatic appearance, the scene became enveloped in cloud once more, and I could not actually be certain that I saw the second figure join the first. It was of course none other than Mallory and Irvine...'