A subterranean relic of the Spanish Civil War hides below this picturesque park.

Some locals believe the fabled lost gold of General Yamashida is hiding somewhere beneath the city.

This frog-themed restaurant was frequented by Picasso, Saint-Exupéry, and more.

"Di amigo y entra" at this Argentinian Middle Earth-inspired pub.

The remains of a former colonial fort on a stretch of beach that is occasionally visited by crocodiles.

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

A crumbling island fortress that seems to be covered in a field of stone crosses but is simply incomplete.

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

The ruins of a military fortification sit atop this mountain.

A 2017 crowdfunding campaign saved this historic castle from being destroyed.

This tiny cafe is one of the last meeting places of its kind, allowing revolutionaries a place to plot.

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

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.

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

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

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

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

Abandoned blockhouses from Nazi Germany's Atlantic Wall erode into the sea on a French beach.

This striking fort on the Maginot Line looks just as it did after being destroyed in the Fall of France.

This bunker in northern France was built by Nazi German forces with the intention of launching up to 50 V2 rockets at London each day.

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

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

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

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