Is this rock trying to convey a secret message? See more in Season 1, Episode 7, "Aliens Codes and Messages." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at http://history.com/schedule. #AncientAliens Subscribe for more from Ancient Aliens and other great ...

Might there be a connection between all these missing person cases--one possibly involving otherworldly portals and even extraterrestrial beings? See more in this scene from Season 1, Episode 10, "Gone Without a Trace." Watch your favorite episodes of Ancient Aliens on The HISTORY Channel ...