Ancient Aliens Top 20 per IMDb presents a list and summary of episodes which are ranked as the show’s most popular on IMBd. Ancient Aliens is an American television series produced by Prometheus Entertainment that explores the hypothesis of ancient astronauts in a documentary format. At the release of this presentation the show has 236 episodes under its belt. And credit is due when it’s due. The series is inspired by the decades long research of Erich von Däniken, Zecharia Sitchin, and other pioneers in the field. Two of the most featured guests are author David Childress and Giorgio Tsoukalos.