William James Sidis spoke 25 languages and had an IQ 100 points higher than Albert Einstein's, but the smartest man in the world just wanted to live his life in seclusion.

From Ted Bundy to John Wayne Gacy, John E. Douglas has interviewed just about every serial killer in recent history. Here's how he learned what made them tick.

Garry Hoy died on July 9, 1993, after performing a "party trick" that involved throwing himself against the windows on the the 24th-floor of his office building.

A humanoid monster with fangs, antlers, and glowing eyes, the Algonquian Wendigo either devours its victims or possesses their spirit and body.

Chris Farley's death in December 1997 was caused by a "speedball" mix of cocaine and morphine — but his friends think there's more to his tragic story.

The Godfather of the Guadalajara Cartel, Miguel Ángel Félix Gallardo spent 18 years growing his empire. But the brutal murder of an undercover DEA agent in 1985 who infiltrated his cartel would be his downfall.

Said to measure seven feet tall with massive wings and glowing red eyes, the Mothman is a cryptid who has allegedly been sighted across West Virginia since the mid-1960s.

Ivan IV Vasilyevich rose to power in the 16th century to become the first tsar of Russia — and earned the nickname "Ivan the Terrible" along the way.

River Country mysteriously shut down in 2001 — and instead of demolishing the once beloved water park, Disney abandoned it, allowing it to rot in plain sight for nearly two decades.

The iconic movie Goodfellas chronicles the lives of real gangsters like Henry Hill, Billy Batts, Tommy DeSimone, and Jimmy Burke — but it only tells part of the story.