Hidden Peak
He led the International Himalaya Expedition (IHE) 1930 to Kangchenjunga, and another one, IHE 1934, to the Baltoro-region in the Karakorams, especially to explore the Gasherbrum-Group. This expedition made the first ascent of Sia Kangri and some of its sub-peaks and provided detailed information about the accessibility of the 8000ers Gasherbrum I and II. The first ascent of Gasherbrum I in 1958 was accomplished via the route proposed by Dyhrenfurth following the so-called IHE-spur and the SE-ridge.