100-windowed castle turned art gallery, built by one dedicated mason.

A bike train runs along a disused railway line through the tranquil French countryside.

This 14th century wine cellar is home to the oldest barrel-stored wine in the world.

This modern museum of Mediterranean culture is surrounded by a surreal concrete honeycomb.

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

A massive base for the Nazis' most formidable weapon in the Atlantic.

This hidden garden boasts amazing views of Lyon.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.

For more than a century, Parisians have come for affordable dishes in a grand converted train station.

The Church of the Annunciation was carved into the face of a cliff, just like the rest of the town of Haute-Isle.

This mural painted by Keith Haring was done without payment as a gift to entertain the children at the Hôpital Necker.

A small house sits between two huge rocks, with its back to the sea.

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

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

An Orthodox church built by the Royal Family for the Russian community exiled to the French Riviera.

Marie Antoinette and Napoleon Bonaparte were fans of this 200-year-old French chocolatier.

A quaint medieval millhouse hovers surprisingly above the waters of the Seine.

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

Marvel at the opulent Art Nouveau interior while dining on dirt-cheap French classics.

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.

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

The world's tallest bridge is also possibly the most elegant.

The birthplace of the ferocious William the Conqueror, this castle is awash in medieval history.