The only remaining collection of flayed figures made by French "madman" Honoré Fragonard.

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

The largest underground church in Europe.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

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

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

Where the high court feasted, frolicked, and high courtesans put their royal lovers' diamonds to the test.

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

This massive blockhead sculpture hides an entire library.

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

An icy lake tucked among jaw-dropping alpine panoramas.

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.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

A modern-day Lascaux cave underneath Paris.

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

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

Hundreds of hidden passageways weave through the old quarters of Lyon.

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."

The curious underground history of keeping Paris clean.

A unrivaled and rather horrifying collection of wax dermatological models.

One of the greatest maze designer’s greatest mazes.

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

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