The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A brush maker used his factory to protect blind Jews from the Gestapo.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

Straight out of a nightmare, barcode-faced babies climb up and down Prague's television tower.

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

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

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

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

Throughout this shopping mall are medieval ruins that were discovered during the mall's construction.

An enormous and lavish Gothic church in Czechia.

This automated sculpture of two men peeing will spell out text messages with their micturition.

This spooky statue sits outside a famous Prague theater.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

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

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

It's good luck to be mocked by this monkey.

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

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

This subterranean studio is filled with fascinating kinetic art.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

There are two dozen tanks just sitting in an open field in Lower Saxony.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.