Underground monastery and fortress.

Small church on top of a huge rock column.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

An astounding collection of taxidermy, fossils, skeletons, and even a few strange live beasts.

This Corsican Neolithic site is full of pre-Roman megalithic structures that may or may not be penises.

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

Exquisite examples prehistoric bas-relief carvings.

Home to the "Rat King" of Nantes and other wonders of the natural world.

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

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

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

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

A huge Megalithic chamber tomb located behind a cafe.

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

A neighborhood church's unusual abstract stained glass was the final project of avant-garde artist Jean Cocteau.

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

A sanctuary for wolves in a community which once trembled in fear of the murderous "Beast of Gévaudan."

An unsettling shrine dedicated to the ravenous beast that prowled 18th-century France.

This army of concretions is an unexplained geological phenomenon unlike anything else in the world.

Despite centuries of architectural innovation, this French castle is being built like it's the 13th century.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

A museum dedicated to linguistics, from how babies learn to talk to endangered and extinct languages.