 It tells the story of United States Army officer John Wesley Powell, who was the first to travel down the Colorado River, and the dangers that he and nine other men had to face while making a map of the region during their 1869 expedition.Hired by Walt Disney Studios in 1959 as a technical adviser, Otis R. Marston led a film crew through the Grand Canyon to film river running and background scenes for the film.Parts of the film were shot at the Big Bend of the Colorado River, Professor Valley, Arches, Dead Horse Point, Dewey, Castle Valley, and Westwater Canyon in Utah.