This artificial cave looks like something out of a fairytale.

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

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

A steampunk-styled three-floor factory churning out art, activism, and electronic beats.

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

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

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

Macabre astrological automaton clock dating to the late 1400s.

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.

Amsterdam's Red Light District leaves little to the imagination.

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

Europe's official "zero-level," the equator of elevation.

This bird-loving brewery is situated in an old municipal bathhouse, nestled beside a 300-year-old windmill.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

This cheese shop also houses a museum devoted to Dutch dairy.

Famed for its pie, this eatery has a hidden tunnel that allowed Catholics to secretly walk to church during the Reformation.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

The attic of a four-century-old canal house hides a clandestine church.

The history and future of cannabis.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A curious collection dedicated to human and animal anatomy and pathology.