The fairy tale castle of the "fairy-tale king."

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

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.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

An eerie, derelict amusement park in Berlin.

A rare chance to ride one of the few continuous elevators still in operation.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

Nearly every wall in this French villa has been "tattooed" by artist Jean Cocteau and other famous painters.

This massive blockhead sculpture hides an entire library.

A reconstruction of a classic mansion on the island of Delos was designed for a historian and archaeologist.

A place to see how French aristocrats lived in the early 1900s.

Artist's eccentric property excessively decorated with found objects and work of his own.

An Orthodox church built by the Royal Family for the Russian community exiled to the French Riviera.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

Home to the "Rat King" of Nantes and other wonders of the natural world.

An often-shuddersome journey into a low-tech, robotic themepark.

A French library that makes sure its love of books is writ large... giant in fact.

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

This modern museum of Mediterranean culture is surrounded by a surreal concrete honeycomb.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

An enchanting work of outsider art, full of whimsical sculptures and carvings.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This professional clown's home is an outsider art wonderland.