He made the first solo ascent of Mount Everest and, along with Peter Habeler, the first ascent of Everest without supplementary oxygen. He was the first person to climb all 14 eight-thousanders, doing so without supplementary oxygen. Messner was the first to cross Antarctica and Greenland with neither snowmobiles nor dog sleds and also crossed the Gobi Desert alone. He is widely considered to be the greatest mountaineer of all time.
