A French artist's vague warning hangs over Belleville.

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

A medieval church with largest and oldest collection of Renaissance frescoes in France.

This innocuous-seeming building is actually the remnant of a major wartime brothel.

The former home of France's controversial pop maestro is almost completely covered in ever-changing tributes and graffiti.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

The famous winding walk at Chartres is surrounded in mystery and myth.

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

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

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

A modern-day Lascaux cave underneath Paris.

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

A unrivaled and rather horrifying collection of wax dermatological models.

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

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

France's national museum of scientific and industrial instruments.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Paris' linguistic guide to the international language of, yes, love.

Abandoned railway line circling the city of Paris.

An intricately decorated tiny place of worship.

On this romantic tidal island reachable only at low tide the tomb of a famous French writer overlooks the sea.