This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

A small church ornamented with medieval erotic sculptures.

A functioning Roman-era aqueduct and bridge in rural southwest France.

Small French town or alien garage?

Green labyrinth formed by a karstic maze hidden in a preserved oak forest.

Every half hour, the flow of this unusual spring cycles between a rush of water and barely a trickle.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

Beneath the city of Lourdes, France is a massive, concrete church.

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

This crack in France's seaside cliffs once hid a sinister secret.

The ruins of a medieval castle linked to the murderous French lord that inspired the famous legend of Bluebeard.

This small island, a byproduct of 19th-century canal construction, is now home to a charming Japanese garden.

The sunken structure looks like the victim of a catastrophic flood.

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

An aluminum skeleton brings Chinese mythology to the French shore.

The haunting concrete remains of a Nazi pebble crusher can still be found in this small French commune.

An isolated 17th-century chapel on a remarkable site once dedicated to Celtic sun worship.

The precise origins of this pink sandstone temple are unknown.

Old vessels have been transformed into artistic canvases in this unusual cemetery.

On this romantic tidal island reachable only at low tide the tomb of a famous French writer overlooks the sea.

An abandoned beach resort in Normandy reclaimed by artists.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.