Eyewitness Dave Surber investigates a mysterious monolith possibly left behind by aliens, in this bonus clip from Season 2, "Mutant Mummy & Alien Monolith." Watch all new episodes of The Proof Is Out There, Fridays at 10/9c, and stay up to date on all of your favorite The HISTORY Channel shows ...

Ancient Astronaut Theorists believe that the Rudston Monolith possesses unusual powers that spark strange phenomenons, in this clip from Season 17, "Mystery Of the Standing Stones." #AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: ...