Did you know there was a period of time when the U.S. government secretly used the public to test biological weapons? Some sites included rural Georgia, San Francisco Bay, and the New York City subway system.

The Backstory: The Horrifying Afterlife of Lincoln's Guests at Ford's Theater
10:11

The Backstory: The Secret NASA Test That Almost Ended the Space Race
08:04

The Backstory: Space Junk Falling From the Sky
08:43