An Italian mountaineer, explorer, and author from South Tyrol. He made the first solo ascent of Mount Everest and, along with Peter Habeler, the first ascent of Everest without supplemental oxygen. He was the first climber to ascend all fourteen peaks over 8,000 metres (26,000 ft) above sea level without oxygen. Messner was the first to cross Antarctica and Greenland with neither snowmobiles nor dog sleds. He also crossed the Gobi Desert alone. He is widely considered one of the greatest mountaineers of all time.