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.

In Ireland, the notion of the fairy folk dates back thousands of years and originates with stories of powerful shining beings who came down from the sky. Could these tales have been inspired by ancient alien visitation? And if so, do the Shining Ones still inhabit the Irish mounds, existing in a parallel dimension?