Ancient Astronauts

Extraterrestrial beings called ancient astronauts or ancient aliens have visited Earth, and this contact is connected with the origins or development of human cultures, technologies, and religions. A common variant of the idea include proposals that deities from most, if not all, religions are actually extraterrestrials, and their technologies were taken as evidence of their divine status. These proposals have been popularized, particularly in the latter half of the 20th century.
Proponents of ancient astronaut theories often maintain that humans are either descendants or creations of 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". Other proposals include the idea that civilization may have evolved on Earth twice, and that the visitation of ancient astronauts may reflect the return of descendants of ancient humans whose population was separated from earthbound humans.