Crash Canyon, Remains of a 1956 Air Collision, Mile 63.
At approximately 1031, 1 June 30, 1956, a Trans World Airlines Lockheed 1049A, N 69020, and a United Air Lines Douglas DC-7, N 6324C, collided at about 21,000 feet 2 over Grand Canyon, Arizona. Both aircraft fell into the Canyon near the confluence of the Colorado and Little Colorado Rivers. There were no survivors among the 128 persons aboard the flights (70 aboard TWA and 58 aboard United). Both aircraft were destroyed.
https://en.m.wikipedia.org/wiki/1956_Grand_Canyon_mid-air_collision