Ah, flying in the 1950s. Fancy clothes, good food, smoking in the airplane, and the chance to see sights you'd never get to see otherwise. Two planes flying over the Grand Canyon on a summer day in 1956 should have passed by perfectly fine, and probably would have on any other day. But tragedy would strike over one of the most beautiful places on Earth, changing the aviation industry in one horrifying moment.

Videos:

• Fatal Collision Over the Grand Canyon | America's Worst Disaster | United 718 and TWA 2

• Air Collision Over The Grand Canyon | Mayday | On The Move

• Historic Archaeology: The 1956 Grand Canyon Aviation Accident by Ben Carver (playlist)

Articles and books:

• Historic Plane Wreck Site Protected
• The Site of a 1950s Plane Crash Just Became a National Landmark But the Park Service won't tell you how to get there.
• CAB accident report