A medieval military street hidden beneath a charming French fishing village.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

Museum in a swimming pool where the water still flows.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

An ancient monastery, a locked room, and a mysterious book heist.

An icy lake tucked among jaw-dropping alpine panoramas.

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

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

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

Monsters and miniatures are held in equal esteem at this wondrous museum.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

Historic medieval fortified city in southwest France.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

Ghosts of France's colonial past.

The largest underground church in Europe.

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

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

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

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

A subterranean shelter remains intact under a busy Paris railway station.

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

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

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