Are There Lost Alien Civilizations in Our Past?
10:58
Why Aliens Might Already Be On Their Way To Us
9:55
Is Civilization on the Brink of Collapse?
10:42
What Do Alien Civilizations Look Like? The Kardashev Scale
12:31
The Last Human – A Glimpse Into The Far Future
13:59
There Are Thousands of Alien Empires in The Milky Way
9:35
Ancient Life as Old as the Universe
11:50
The 'Ancient Aliens' Idea is More Realistic Than You'd Expect...
9:53