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

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

Beautiful carved tunnels.

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

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

This professional clown's home is an outsider art wonderland.

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

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

A Gothic cathedral created from volcanic rocks.

BDSM, 1930s Style.

Historic medieval fortified city in southwest France.

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

Hundreds of hidden passageways weave through the old quarters of Lyon.

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

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

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

One of the greatest maze designer’s greatest mazes.

A unrivaled and rather horrifying collection of wax dermatological models.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

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

A subterranean shelter remains intact under a busy Paris railway station.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

A haunting collection of the vanished and disappearing natural world.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.