Before the world was industrialized less than 200 years ago . . it smelled really different! They didn’t have to deal with the smell of gasoline fumes, burning rubber or oil, or the output of giant smokey factories. But imagine 3 1/2 million pounds of manure dumped onto the streets of New York City every day! Were they nose blind?

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