Arrows show the approximate locations where the TWA and United planes crashed into the North Rim of the Grand Canyon. The collision killed 128 passengers and crew, making it the worst air disaster in commercial aviation at the time. The United and TWA flights that left Los Angeles International Airport on June 30, 1956, were among those special first-class-only flights. The Grand Canyon disaster also became a lesson to the industry against trusting the odds. And the world was shocked with the Grand Canyon disaster, too.