An enchanting work of outsider art, full of whimsical sculptures and carvings.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

Series of underground houses inhabited continuously for centuries.

This otherworldly French waterfall looks like its waters have turned to stone.

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

This medieval tower is all that remains of the castle where Joan of Arc was held before being burned at the stake.

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

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

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

The sunken structure looks like the victim of a catastrophic flood.

The construction of a tram line unveiled hidden remnants of the old medieval city.

A French library that makes sure its love of books is writ large... giant in fact.

A quaint medieval millhouse hovers surprisingly above the waters of the Seine.

This ancient theater was once the home of fierce gladiatorial battles.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

A centuries-old complex of hand-dug stone chambers has sheltered locals in times of trouble.

One of the world's most complex timepieces.

The Church of the Annunciation was carved into the face of a cliff, just like the rest of the town of Haute-Isle.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

A medieval church with largest and oldest collection of Renaissance frescoes in France.

The 16th-century church was kept in its ruined state as a reminder of the casualties of World War I.

A tiled, multi-level garden of survival in Lyon.

The world's largest reflecting pool is just two centimeters deep.

A chapel on a volcanic core, marking the end of a successful journey.