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

This Parisian fountain is a little bit fantasy and a little bit nightclub.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

Statue of death tucked in the University of Medicine courtyard.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

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

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

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

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

A mechanized clock where a man fights off a dragon, crab, and rooster.

Indents in the pavement are all that remain from a grisly death machine in Paris.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

France's national museum of scientific and industrial instruments.

This museum houses an imposing skeleton army comprised of creatures great and small.

The oldest stone house in Paris was built by its most famous alchemist.

Abandoned railway line circling the city of Paris.

France's most famous cemetery, with some of its most curious tombs.

A series of bronze circus performers spread throughout a Slovakian shopping center.

Brass plaques embedded in pavement preserve the memories of those who lost their lives at the hands of Nazis during World War II.

According to the local legend, these boys and ducks were turned to stone by an angered water goblin.

An ode to a soldier who came to town, fell in love, then began making his own sparkling wine.