For 30 years, Boy Scout troop leader and church council president Dennis Rader was secretly the BTK murderer — while looking like the perfect family man to his neighbors in Kansas.

In May 2012, Luka Magnotta murdered a university student named Jun Lin, chopped up his body, and mailed his limbs throughout Canada, then shared a video online of his crimes titled "1 Lunatic 1 Ice Pick."

Despite his mythic handicap, Ivar the Boneless was the most fearsome Viking of his time and conquered England with his heathen army.

Known informally as the Japanese mafia, the Yakuza are a 400-year-old criminal syndicate that carries out everything from human trafficking to real estate sales.

The "Swamp Sasquatch" known as the Florida Skunk Ape is a 6'6", 450-pound hairy, smelly ape that roams the Everglades — or so believers say.

Reinhard Heydrich had many nicknames: "the Blond Beast," "the Hangman," and "the Butcher of Prague" — but none of them quite captured just how ruthless he was.

When the end of Prohibition finally came with the ratification of the 21st Amendment in 1933, America kicked off perhaps the biggest impromptu party the country had ever seen.

Groupies were more than just the sex that came with music stardom — they were muses who left their marks all over the history of rock music.

Established after the Bolsheviks took power in 1919, the gulags were forced labor camps where at least 1 million people died over the next 50 years.

Jack Unterweger went to prison for murder, then found fame as an author — before strangling several women to death in Austria and Los Angeles between 1990 and 1991.

The enormous ocean sunfish known as the Mola mola can grow to be 5,000 pounds and 14 feet long, making it the world's largest bony fish.