A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

An old asylum graveyard that's been abandoned for half a century attracts those seeking a dark thrill.

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Countless grotesque faces stare out from this eerie Prague art wall.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Two stunning 17th-century libraries and a cabinet of curiosities.

A Jenga-style cylindrical tower of books that appears to go on forever.