An architectural oddity of six stories, accessed by graceful ramps.

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.

The construction of a tram line unveiled hidden remnants of the old medieval city.

This otherworldly French waterfall looks like its waters have turned to stone.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

Located in the house where Gustave Flaubert was born, this odd museum has more to do with medical grotesquery than the Western novel.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

One of the world's most complex timepieces.

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

Nicknamed the "Museum of Horrors," this French anatomical collection has been fascinating visitors for over a century.

A unique underground structure dating back to the 1st century BC.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

A quaint medieval millhouse hovers surprisingly above the waters of the Seine.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

Collection of antique taxidermy and natural specimens, near one of Paris's oldest flea markets.

This ancient theater was once the home of fierce gladiatorial battles.

An art world insider finds himself battling for his artistic home.

The Church of the Annunciation was carved into the face of a cliff, just like the rest of the town of Haute-Isle.

Statue of a decomposing prince that once held his heart in its hand.

A centuries-old complex of hand-dug stone chambers has sheltered locals in times of trouble.

Hundreds of dwarf beeches create an unusual, haunting forest in the north of France.

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