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

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

The world's tallest bridge is also possibly the most elegant.

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

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

Sleep in a climate-controlled plastic bubble for the night.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

An aluminum skeleton brings Chinese mythology to the French shore.

Beautiful carved tunnels.

Avant garde house of Pierre Cardin on the Cote d’Azur.

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

The fantastic architectural models of a French traveler.

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

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

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

Historic medieval fortified city in southwest France.

The largest underground church in Europe.

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

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

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

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

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