This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

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

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

An aluminum skeleton brings Chinese mythology to the French shore.

A medieval military street hidden beneath a charming French fishing village.

A Gothic cathedral created from volcanic rocks.

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

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

Historic medieval fortified city in southwest France.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

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

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

An icy lake tucked among jaw-dropping alpine panoramas.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

Ancient paintings known as the "Sistine Chapel of Cave Art."

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.