The Builders T-Shirt

Proponents of ancient astronaut theories often maintain that humans are either descendants or creations of extraterrestrial beings who landed on Earth thousands of years ago. An associated idea is that much of human knowledge, religion, and culture came from extraterrestrial visitors in ancient times, in that ancient astronauts acted as a "mother culture". Ancient astronaut proponents also believe that travelers from outer space known as "astronauts" or "spacemen" built many of the structures on earth such as the pyramids in Egypt and the Moai stone heads of Easter Island or aided humans in building them.