A massive, secret marina for the Nazis' most formidable weapon in the Atlantic.

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

The largest crypt ever constructed in France was built in the 11th century on an ancient Druid sacred site.

This otherworldly French waterfall looks like its waters have turned to stone.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

If they push on just the right spot, even the weakest person can move this titanic boulder.

An art world insider finds himself battling for his artistic home.

Dedicated to the history and culture of smoking, this small museum now includes a vape lounge.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

Hundreds of dwarf beeches create an unusual, haunting forest in the north of France.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

The post-apocalyptic remnants of a bucolic town ruined by a plane crash.

A centuries-old complex of hand-dug stone chambers has sheltered locals in times of trouble.

The remains of 40,000 humans, meticulously stacked in a tiny churchyard shed.

A swath of France so devastated by war it is still forbidden to go there.

Nicknamed the "Museum of Horrors," this French anatomical collection has been fascinating visitors for over a century.

The Cimetière des Chiens et Autres Animaux Domestiques is one of the oldest pet cemeteries in the world.

This collection of French root art looks like an indoor fairy wonderland.

One woman's decades-long obsession with the "La Fée Verte."

Museum in a swimming pool where the water still flows.

Ghosts of France's colonial past.

An enchanting work of outsider art, full of whimsical sculptures and carvings.

An odd museum dedicated to French fakes.