National Geographic : 1956 Oct
494 I. Lee Wells, Jr. Explorer II Strains at Its Leashes. Minutes Later It Headed for the Stratosphere On Armistice Day, 1935, Captains Orvil A. Anderson and Albert W. Stevens cast off from the Stratobowl near Rapid City, South Dakota. Their helium-filled balloon rose 72,395 feet above sea level, still the record altitude for a manned balloon. For an hour and forty minutes it dangled more than 13 miles above the earth, man's longest stay at such a height. Flight sponsors were the National Geographic Society and the United States Army Air Corps.