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

An icy lake tucked among jaw-dropping alpine panoramas.

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.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

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

One of the greatest maze designer’s greatest mazes.

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.

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

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

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

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

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

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

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

France's national museum of scientific and industrial instruments.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

This Parisian café sticks almost exclusively to an ethos of reuse.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

Notorious artist squat renovated into legal studios.

Abandoned railway line circling the city of Paris.