Tilman was involved in two of the 1930s Mount Everest expeditions - participating in the 1935 Reconnaissance Expedition, and reaching 27,200 feet without oxygen as the expedition leader in 1938. He penetrated the Nanda Devi sanctuary with Eric Shipton in 1934, and in 1936 he went on to lead an Anglo-American expedition to Nanda Devi. With the support of a team which included Peter Lloyd and H. Adams Carter, Tilman and Noel Odell succeeded in making the first ascent of the mountain, which remained the highest summit climbed by man until 1950. Tilman later described their arrival on the summit: