In this image released by mountain guide Adrian Ballinger of Alpenglow Expeditions and taken Saturday, May 18, 2013, climbers navigate the knife-edge ridge just below the Hillary Step on their way to the summit of Mount Everest, in the Khumbu region of the Nepal Himalayas. Sixty years ago Wednesday, Sir Edmund Hillary and climbing partner Tenzing Norgay were the first to set foot on the summit of Mount Everest, the highest point on earth on May 29, 1953. (AP Photo/Alpenglow Expeditions, Adrian Ballinger)

Adrian Ballinger