An abandoned saucer-shaped monument in the Bulgarian mountains.

This huge metal monument is slowly being stripped to its concrete skeleton.

The remains of a sunken military ship wreck visible through clear water.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

An old department store turned Nazi prison turned artist commune.

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

A curious cave church carved into the face of a cliff.

On top of a resort town as old as the Bronze Age sits an incredible war memorial statue overlooking the beaches below.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

Yugoslavia's biggest underground airport lies in ruins.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

A miniature train-ride through Slovenia's largest cave system.

Celebrated example of Ottoman architecture that also served as a site for brutal massacres.

The sad remains of a monument to martial arts legend and movie star Bruce Lee—in the middle of Balkans.

These warring psychedelic crags commemorate an unsuccessful military operation.