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

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

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

An eerie, derelict amusement park in Berlin.

An impressive ensemble of sculptures that survived the Soviet regime.

Plaques celebrating Lithuanian writers freckle a wall of this picture-perfect path.

Underwater roads undetectable from the surface used for escape routes from foreign invaders.

Once known throughout Europe, this tiny and unusually progressive 18th century micro-nation within Lithuania now lies in ruins.

A breathtaking bridge that crosses a vast gorge over a river's torrents, and has a tale of a devil architect attached.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.

This lovely little bridge hidden in a Switzerland gorge is essentially a fairytale.

This folk museum is devoted to small figurines of provincial village life.