Are you intrigued by the thought of aliens visiting Earth and leaving behind signs like cave drawings and pyramids and geoglyphs? Did you know that many of these ancient sites are part of what’s called the Great Circle, appearing along an exact circle within a tenth of a degree of each other?

The Backstory: The A.I. Bubble: We’ve Been Here Before
11:49

The Backstory: The Islands Where Millionaires Went to Disappear
10:19

The Backstory: Walt Disney: How Desperation Led to a Billion Dollar Mouse
10:30