Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

A small town hallucinates en masse - Bad bread, or CIA science project?

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

1920's reinforced concrete church by architect Auguste Perret changes the face of modern design.

The historic Masonic Lodge in which the first-ever female Mason was initiated.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.

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

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

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

The remains of 40,000 humans, meticulously stacked in a tiny churchyard shed.

The personal library of the founder of modern neurology is open to visitors.

One of the oldest masonic museums in Paris.

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

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

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

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

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

Museum in a swimming pool where the water still flows.

Noirish green neon marks the location of one of the oldest private detective agencies in France.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

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

A Gothic cathedral created from volcanic rocks.

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