Why "Gorilla Man" Earle Nelson was America's worst murderer long before the term "serial killer" was even invented.

The macuahuitl was plenty deadly enough to take you down. But the Aztecs would rather bring you to the edge of death, then sacrifice you alive.

The glyptodon may seem like just a big armadillo, but it was the size of a car and could crush early humans with its clubbed tail.

Frito Bandito spent four years hawking corn chips to kids. Unfortunately, he embodied the worst of Mexican stereotypes.

Chesty Puller has received the most medals of any Marine. He earned every one of them.

Karl Denke was an upstanding member of his community – until they realized he was turning humans into pickled pork, belts, and suspenders.

The sea is basically the Pacific version of the Bermuda Triangle, complete with mysterious disappearances, sea monster sightings, and ship sinkings.

Woodes Rogers made it his life's work, and risked his family's fortune, to rid the world of pirates.

While beautiful, the Portuguese man of war packs a powerful venom that could give you severe muscle pain, make you vomit, or even kill you.

Keikaimalu, the world's first known surviving wolphin, was born to a male false killer whale and a female bottlenose dolphin.