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

A self-built mosaic house and sculpture park.

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

Museum in a swimming pool where the water still flows.

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

Dedicated to the art of hunting, with juxtapositions of contemporary art.

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

The oldest and smallest cemetery in Paris is only open to the public twice a year.

Architect Le Corbusier built his friend a cubist house to match his impressive collection of cubist art.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

Beautiful carved tunnels.

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

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

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

An aluminum skeleton brings Chinese mythology to the French shore.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

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

The famous winding walk at Chartres is surrounded in mystery and myth.

A Gothic cathedral created from volcanic rocks.

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

The largest underground church in Europe.

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

Science fiction's grandfather has a fittingly marvelous tomb.