Today, there are only three Jack the Ripper letters that investigators believe may be credible. But only the "From Hell" letter was sent along with a human kidney.

Ancient Roman graffiti in Pompeii has been found on walls throughout the city, nearly perfectly preserved since the eruption of Mount Vesuvius in 79 A.D.

Researchers used 200-year-old records to uncover the Colosseum-like arena where gladiators and animals fought to the death in the ancient town of Mastaura in western Turkey.

On July 27, 1996, Eric Rudolph planted a bomb at Centennial Olympic Park in Atlanta, Georgia. He then targeted two abortion clinics and a lesbian bar before vanishing into the North Carolina wilderness.

Built in the 13th century by Clan Maxwell, Caerlaverock Castle is a striking triangular fortress on Scotland’s southern coast — which can still be visited today.

Richard Jessee was driving his ATV near his mining claim when the bear attacked him out of nowhere and destroyed his vehicle and cell phone. Then it kept coming back every night for a week.

In 1766, Jeanne Baret secretly joined the first French naval voyage around the world by pretending to be a cabin boy.

Despite its monstrous jaws and teeth, the wolf eel is actually a gentle giant that’s even known to cuddle with divers.

Mark Kilroy was a University of Texas student on spring break in March 1989 when he was tortured and murdered by Adolfo Constanzo’s cult in Matamoros, Mexico.

Standing on a tiny island in Lough Key in Ireland, McDermott’s Castle has a rich and eerie history that dates back to the 12th century.

Until the foundation of Alexandria, Thônis-Heracleion served as Ancient Egypt's largest port city on the Mediterranean Sea, where Greek merchants dominated trade.