A series of playful yellow penguins share a serious message about the environment.

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

This artificial cave looks like something out of a fairytale.

The first museum in the world devoted to sexual gadgetry.

Walk through Czech history in Prague's largest graveyard.

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

Macabre astrological automaton clock dating to the late 1400s.

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

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

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

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

What looks like a crashed Zeppelin is actually a bright, airy reading room perched atop a modern museum.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

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

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

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

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

Achill's most recently abandoned village dates back to to the Age of Enlightenment.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

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

This forgotten chalk mine was reopened thanks to a massive effort from the local community.

The oldest private art gallery in all of Hungary.

The ruins of a 12th-century Cistercian monastery can be found alongside World War II tank traps and pillboxes.