French commune at the heart of conspiracies.

An ancient ossuary in Rouen.

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

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

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

Walk through living pictures and music in the Cathedral of Images.

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

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

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

The Sun King's military models, saved from the Louvre.

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

The first green space constructed on an elevated viaduct.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

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

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

Historic medieval fortified city in southwest France.

Pitié-Salpêtrière was the dumping grounds for women who received the dreaded diagnosis of "hysterical."

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.