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

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

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

France's national museum of scientific and industrial instruments.

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

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

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

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

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

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

A haunting collection of the vanished and disappearing natural world.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

This massive library holds what was once the largest book collection in the world.

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

Notorious artist squat renovated into legal studios.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A kaleidoscopic warehouse-maze of handmade neon signs.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

An exquisite tunnel of cascading flowers.

A psychedelic labyrinth on the San Francisco bay.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.