Dyhrenfurth received a permit from the Nepalese authorities on May 10, 1961, for an American expedition to climb Mount Everest in the spring of 1963. On May 1, Whittaker and Gombu reached the summit of Mount Everest by the
South Col route used by the
successful British expedition of 1953. On May 22, Unsoeld and Hornbein completed the first ascent of the West Ridge, descending by the South Col, thus completing the first traverse of Everest. That same day, Bishop and Jerstad reached the summit by the South Col route. The two pairs of climbers met up high on the mountain, and made their descent in the gathering darkness. From midnight until 4:00 am, they
bivouacked high on the mountain, without sleeping bags, tents or bottled oxygen. All survived, though Unsoeld and Bishop suffered from
frostbite, resulting in the amputation of toes. On July 8, 1963, President
John F. Kennedy presented the
National Geographic Society's Hubbard Medal to Dyhrenfurth at a ceremony in the flower garden of the
White House. The surviving members of the expedition were also present. Kennedy told Dyhrenfurth that "we followed your actions with the greatest pride." In 1965 Dyhrenfurth's film
Americans on Everest aired on
CBS television as the first
National Geographic special. ==1971 International Expedition==