The first green space constructed on an elevated viaduct.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

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

Notorious artist squat renovated into legal studios.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Central Europe's largest collection of mini-bottles is on display at this museum devoted to a bitter Hungarian liquor.

The romantic garden was the epicenter of the Hungarian art scene in the 1880s.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

Museum dedicated to the terror regimes of Hungary.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

The last municipal pneumatic post system in the world was in operation for over 100 years, and may run again.

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

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

One man's personal kunstkammer, museum and shop.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The patron saint of spinsters grasps a container of dried blood.

King Ludwig I's collection of beautiful women.

The footprint of a frustrated devil in Munich's Cathedral.

Two stunning 17th-century libraries and a cabinet of curiosities.

Microscopic scenes; some call it novelty, some call it art.