These ruins reveal the remarkably intact layout of a Roman marketplace.

A castle-like sea fort from the 17th century is now a museum to oyster farming.

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

Trek up this glacier before it disappears.

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

These colorful French islands spent a stint bootlegging booze during American Prohibition.

The eclectic observatory castle of a 19th-century astronomer and explorer.

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

The remains of this castle, known as the Witch’s Eye, watch over the Thur Valley.

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

One of the great treasures of Neolithic art lies within this carefully constructed pile of rocks.

Longest canal tunnel in the world, abandoned in the 1960s.

This mountain trail inspired Nietzsche to complete his magnum opus.

Folklore and history carved into Brittany's coast.

This French "sea of rocks" is packed with stunning rock formations and its own medieval castle.

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

This 1,400-year-old abbey was once a powerhouse for music and intellectualism known across Normandy.

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

Resting on a hill overlooking the coast, these medieval ruins look completely deserted save for their restored chapel.

From carts to cars, this leftover Roman bridge in France has managed to survive for centuries.

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.

These medieval ruins have survived since the 12th century, even providing shelter from the Nazis.

A sublime medieval path adorns the marble floor of one of the most beautiful Gothic cathedrals in France.