One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Visit the ancient, mysterious Roman catacombs ... in the Netherlands.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

This German art chapel is perfect for those who like their worship hard, modern, and utterly alien.

A beautiful maze marks where three countries meet.

A distinctive former power plant turned university lecture hall looks like it could make you breakfast.

These tenacious 14th-century towers defied demolition and are now a fairytale vacation rental.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Largest illuminated advertisement sign in the world.

This former steel and coal plant is now a neon-lit industrial fantasia.

The monumental home of Prussia’s eccentric "Cannon King."

The first recognized Neanderthal remains were found in this now-lost cave in 1856.

An electrical pylon under whose legs a normal gauge train can run.

Twisted buildings adorn the banks of the Rhine river.

This futuristic German television spire is actually the world's largest digital clock.

An abandoned underground bathroom is now a space for public art.