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

The hidden lair of an alchemist rediscovered in a 2002 flood.

A Jenga-style cylindrical tower of books that appears to go on forever.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

A French artist's vague warning hangs over Belleville.

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

The narrowest street in Paris.

Beggars were miraculously "cured" of their fake ailments when they returned home to this 17th century Paris slum each night.

This banal Parisian entranceway is not what it seems.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

Original cabaret handbills, posters, and feline artwork are a purrfect highlight of the Museum of Montmartre.

A unrivaled and rather horrifying collection of wax dermatological models.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

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.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

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

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

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

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

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.