This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A little sculpture with a large wardrobe.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Berlin's old airport.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

Real bones which are said to have belonged to a Polish dragon.

A giant floating rubber duck-bunny painted with a different design every year.

A modern reimagining of a medieval city gate.

Four giant movable street lights decorate this modern Rotterdam square.

An early 19th-century English style garden hidden in the Rotterdam cityscape.

Amsterdam's former hotspot for public executions and dissections.

A beautifully eclectic mix of architectural styles.

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

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

An exquisite Baroque church in Vienna's old town.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

This charming pup is meant to celebrate the youth and stubbornness of the city's students.

Old ships and machinery fill a historic harbor in the city that's home to Europe's largest port.