On January 4, 1970, NASA cancelled the Apollo 20 moon mission. This came just six months after Apollo 11 astronauts Buzz Aldrin and Neil Armstrong became the first people to ever set foot on the moon.

Officially, Apollo 17 was the last mission to the Moon. But a retired astronaut claims Apollo 20 was real—and its mission was to salvage a crashed alien spacecraft. Rubber bullets, pepper spray and ...