Europe's second largest ossuary wasn't discovered until 2001.

A mocking tribute to the past and modern leadership of Prague.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

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

An eerie, existential museum dedicated to the author of "The Metamorphosis."

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

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

Street artists transformed an abandoned air vent into the beloved Star Wars robot.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Walk through Czech history in Prague's largest graveyard.

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

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

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

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

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

This statue of a falling man commemorates a teenage martyr of the Hungarian Revolution.

The massive machine creates cracking displays of indoor lightning.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

A museum in the childhood house of a medical pioneer.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Once the home of a hermetic monk, this cave now houses a small church.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

This marine reptile was discovered by one of the 19th century's greatest fossil hunters.