Gravity seems to fail at this intriguing Swedish attraction.

A darkly erotic open-air statuary in Catalonia.

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

An ancient monastery, a locked room, and a mysterious book heist.

The evocative ruins of a medieval village.

Explore an eerie, abandoned medieval citadel.

Deep in the limestone cliffs of the Alabaster Coast, a German fortress built during World War II.

According to a local legend, this peculiar mountaintop rock formation is actually a demon that was turned into stone.

A precariously balanced goose-shaped boulder with a dark legend.

Each of these hand-painted wooden boxes, which date to between the 16th and 19th centuries, contains a genuine human skull.

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

Today this former Nazi concentration camp stands as a poignant memorial to the victims of fascism, and a warning from history.

The second-largest natural arch in the Chartreuse Mountains.

This disused boat elevator was saved from the scrap heap so that visitors could tour its rusting skeleton.

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

The ruins stand as a somber reminder of France’s worst civil catastrophe of the 20th century.

An effigy of a trapped paratrooper dangles from a Normandy church to commemorate one remarkable D-Day event.

A suspended footbridge allows for traversing this gorge carved through the French Alps.

A total of 22 tiny bridges cross this canal of the Yvette River, forming a unique trail.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

A granite rock formation littered with various species of moss, lichen, and fern.

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

For a brief time in 1960s France, families could climb into a tiny submarine and be pulled along an underwater journey.

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