This monolithic slab of art metal crowns a German slag heap.

An industrial relic is now one of Europe's most staggering art spaces.

This "floating railway" is one of the world's oldest monorail systems.

Be it nature, art, or abandoned military architecture this eclectic German "museum" has you covered.

This temple to the sturm and drang of Richard Wagner contains a dragon's cave and reptile zoo full of living "dragons."

What was once a bustling mining installation is now a bustling hub of contemporary art.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

This historical Netherlands fortress still bears the marks of its single siege.

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

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

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.