Noirish green neon marks the location of one of the oldest private detective agencies in France.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Christ's blood allegedly preserved in a Belgian town.

Since 1920, one small company has defined the distinctive chairs of Paris' sidewalk bistros.

Despite centuries of architectural innovation, this French castle is being built like it's the 13th century.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Electrical curiosity museum housed in an old transformer station.

Once the home of a hermetic monk, this cave now houses a small church.

There aren't too many operational funiculars around, but Pittsburgh has two!

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Mysterious rocks that ring musically when struck.

A museum of carnival attractions where you are invited to ride the rides.

The history of radiation is on safe display at the foot of a radiation science laboratory.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Catering to broken dolls for almost 200 years, this repair shop is now a charnel house of doll parts.

A cluttered and astounding collection of antiquities and curiosities.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

There has been an astronomical clock on this spot since the 14th century.

Lie in a hammock where George Washington stood.

Behind a bodega is a small museum of relics and ephemera showcasing the history of New York.

A Collegiate Gothic quadrangle that surrounds an 18th century secondary school whose financing came from the likes of Alexander Hamilton and Aaron Burr, among others.

One woman's decades-long obsession with the "La Fée Verte."

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.