This mountain trail inspired Nietzsche to complete his magnum opus.

Series of underground houses inhabited continuously for centuries.

A remote hilltop covered in giant monoliths haunts the Brittany countryside.

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

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

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

Figures of unknown origin carved into the surfaces of underground caves.

One man's desire to transcend art led to the construction of this outsider chapel.

Artist's eccentric property excessively decorated with found objects and work of his own.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

One of the world's most complex timepieces.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

This hidden garden boasts amazing views of Lyon.

Lyon's "Wall of the Silk Weavers" is one of the largest murals in Europe.

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

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

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

An atmospheric, medieval-themed book store hides in a 13th-century underground space.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

France's high-tech, future-themed amusement park.

Green labyrinth formed by a karstic maze hidden in a preserved oak forest.

Tens of thousands of ancient rock carvings hidden in the heart of a French national park.

The largest crypt ever constructed in France was built in the 11th century on an ancient Druid sacred site.

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