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

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

An icy lake tucked among jaw-dropping alpine panoramas.

A modern-day Lascaux cave underneath Paris.

Ancient paintings known as the "Sistine Chapel of Cave Art."

One of the greatest maze designer’s greatest mazes.

A unrivaled and rather horrifying collection of wax dermatological models.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

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

How did a French journalist’s grave become the sexiest statue in the cemetery?

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

This Parisian fountain is a little bit fantasy and a little bit nightclub.

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

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

Statue of death tucked in the University of Medicine courtyard.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

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.

A surrealist timepiece by the artist of melting clocks.