Everest then and now.
D000064:Acclimatization; D005101:Expeditions / Q000266:history; D049673:History, 20th Century; D006801:Humans; D008297:Male; D009051:Mountaineering; D009390:Nepal; D010100:Oxygen / Q000502:physiology; D010809:Physical Fitness
D010100:Oxygen