In Chicago 1987, local television sets were commandeered by a man in a Max Headroom mask. His explicit and uncensored behavior caught the attention of millions who wondered: Who had the power to take over the airwaves? What was his motive? And if he struck again, what would he do next?

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For roughly a century, from the 1860s to the 1960s, numerous people reported the same bizarre medical malady: horrible toothaches that didn't end until the offending molars exploded — inside their mouths.

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For almost a century, the Hinterkaifeck murders have run cold. Some point to a robbery gone wrong, political extremists, or even familial love triangles as possible motives behind the attacks.

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In a rural German settlement in April 1922, five members of the Gruber family, along with their maid, were slaughtered in cold blood. While the Grubers had been the topic of town gossip for years, not even the police could fathom who might have wanted them dead.

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45 million years ago, a group of monkeys somehow arrived in South America. Some scientists think the primates rafted across on floating islands, while others believe they trekked across a landbridge — a journey that took them millions of years.

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There are two families of monkeys on the planet: the Old World Monkeys, which live in Africa and Asia, and the New World Monkeys native to South America. A discovery in 2015 confirmed that they share a common ancestor — but one major mystery remained. How did it cross the Atlantic Ocean? 

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Outside Glasgow, Scotland, a 1,000-square-foot slab of rock lies buried in a hillside, covered in ancient carvings. Is the Cochno stone the remnant of an ancient ritual, a rocky guidebook, or something more supernatural?

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Inexplicable rumblings from the heavens have dated back centuries. With no connection to the weather, many wonder if these strange noises are due to meteors, sonic booms, or if they're Biblical warnings that the end is nigh.

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Nobody really knows why Houska Castle was built, or why its strange layout seemingly defies explanation. It may be a last defense against a gateway to Hell, or host a portal through space and time. Or perhaps its real purpose is even more obscure…

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Is a castle in the present-day Czech Republic guarding us against unimaginable evil? Built in the 13th century by Bohemian settlers, the layout and history of Houska Castle suggest something sinister lurks there… and legend holds that it sits atop a gateway to Hell. 

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