This former quarry is now a picturesque gorge that hides a sunken lake.

An existential riddle in the world's largest ancient castle.

A spiral staircase twists to the top of this unusual Czech lookout tower.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

Europe's largest natural bridge has a 19th century royal chateau built into its side.

Thirty creepy ghosts now inhabit this decaying 14th-century church.

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

Two monstrous faces loom over a village in Czechia.

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

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

This artificial cave looks like something out of a fairytale.

This doorless 20th-century elevator doesn't stop or slow down.

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

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

What looks like a suicide in progress is actually a statue of Sigmund Freud.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

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

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

A church of bones, decorated with 40,000 human skeletons.

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

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