Ancient Aliens: Top 3 UNBELIEVABLE Alien Petroglyphs

Are these petroglyphs proof that Earth has been visited by extraterrestrials See more in Season 19, Episode 20, The Top Ten Alien Watch your favorite episodes of Ancient Aliens on The HISTORY Channel website at , AncientAliens Subscribe for more from Ancient Aliens and other great The HISTORY Channel shows: Find out more about the show and watch full episodes on our site: Check out exclusive The HISTORY Channel content: History Newsletter Website Facebook Twitter Ancient Aliens explores the controversial theory that extraterrestrials have visited Earth for millions of years. HISTORY is the leading destination for awardwinning original series and specials that connect viewers with history in an inf