Ancient Aliens has followed investigators across the globe as they've gone directly to the sites where signs of alien life have been found. Now, Giorgio Tsoukalos takes a look back at the most incredible evidence ever uncovered that could offer definitive proof that we are not alone in the universe.

Ancient cultures around the world often referred to the gods as the "Immortals" - but could they have encountered extraterrestrial beings that had achieved eternal life? And if these visitors genetically engineered the human race, as Ancient Astronaut Theorists suggest, is it our destiny to become immortals as well?