Ancient Aliens Season 5 E12: Massive stone structures that reach to the heavens... strange, giant figures buried deep in the Earth... and energy emitting spheres connected around the globe... What compelled ancient man to move colossal stones, in some cases weighing thousands of pounds, and to build remarkably similar stone monuments all around the world? From the jungles of Costa Rica to England's rural countryside, ancient people achieved extraordinary feats of construction without advanced tools or technology. Is it possible that extraterrestrials instructed the ancients to build these complex structures? Or were our ancestors driven to create these monoliths in order to reconnect with celestial travelers who once walked the Earth? Could ancient monoliths hold advanced, extraterrestrial powers we have yet to realize? And if so, just what will happen when we unlock the mystery of the monoliths?