From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

Resting on a hill overlooking the coast, these medieval ruins look completely deserted save for their restored chapel.

A massive, secret marina for the Nazis' most formidable weapon in the Atlantic.

An underground city of ancient quarry tunnels hid thousands of Allied soldiers in WWI.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

100-windowed castle turned art gallery, built by one dedicated mason.

Legend has it this 11th-century castle was paid a visit from the devil.

These medieval ruins have survived since the 12th century, even providing shelter from the Nazis.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

Perhaps the most beautiful of preserved saints, with a little help from Paris.

This Parisian gem is one of the most incredible ethnographic museums in the world.

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

Series of underground houses inhabited continuously for centuries.

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

Figures of unknown origin carved into the surfaces of underground caves.

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

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

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

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

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

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

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

The sunken structure looks like the victim of a catastrophic flood.

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