Ancient astronaut theory
The Ancient Astronaut Theory is a fringe theory that claims that the emergence of early human civilization was influenced by extraterrestrial interaction based around a few vague images in ancient sites. Some variations of this theory involve a technologically advanced Atlantean society. This theory is not considered valid by the vast majority of the academic community.
The Ancient Astronaut Theory in science fiction
Despite it's lack of academic credibility, it's romantic appeal makes it a popular feature in science fiction.