Ancient Aliens: Season 21, Episode 1

21 - 1: The Top Ten Extraordinary Discoveries

Ancient Aliens is counting down ten of history's most astonishing discoveries – breakthroughs that challenge traditional beliefs about human history. From a lost city hidden in the Andes to mysterious metal spheres that are not of this world and a sunken city that was said to be the home of the gods, could these discoveries provide proof of extraterrestrial contact?