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

This World War II bunker now survives as a documentation of the Nazi regime and war crimes.

A state-of-the-art medical facility from the Imperial era is now a derelict ruin.

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

Europe's largest natural bridge has a 19th century royal chateau built into its side.

A small man-controlled waterfall powers an Art Nouveau elevator and is accessed via narrow gauge, solar-powered tramway.

Ruins of a German Castle on top of a towering stone pillar.

An engineering wonder at Pillnitz Castle protects a precious 230-year-old flowering shrub.

Slaughterhouse Five opens its dank doors to fans of Kurt Vonnegut.

Video games, body language, and postal history are all on display in this Swiss museum.

Zurich's evolution museum hosts a unique collection of skeletons among its natural history treasures.

This simple apartment may have inspired some of the most important theories in the history of science.

This small museum displays a collection of outsider art and scale models of past "treatments" for mental illness.

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

The alpine falls where Sherlock Holmes apparently met his demise can actually be visited.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

These spooky and unusual stone formations create an underworldly landscape.

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

Caves famous for the dragon-slaying saint who lived there.

This amazing pedestrian suspension bridge in the Swiss Alps would give Indiana Jones nightmares.