An old department store turned Nazi prison turned artist commune.

Cold war icon and onetime "hole" in the iron curtain.

Berlin's old airport.

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

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

The most visited, and possibly most controversial, museum in Germany.

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

An eerie, derelict amusement park in Berlin.

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

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.

A beautifully eclectic mix of architectural styles.

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

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

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

Paris' fabled purveyor of exotic taxidermy and natural history curios.

A haunting collection of the vanished and disappearing natural world.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

Notorious artist squat renovated into legal studios.

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

Budapest's Communist-era statues, banished to the suburbs.

Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

The world's longest outdoor covered escalator system transports commuters through Hong Kong's hilly terrain.