A network of underground water channels that dates back to the Middle Ages.

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

This demon atop the Notre-Dame de Paris looks utterly bored.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

A short distance from the Eiffel Tower is the final resting place of several of the city’s more well-known and interesting characters.

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

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

Where the high court feasted, frolicked, and high courtesans put their royal lovers' diamonds to the test.

A charming flea market shop dedicated to retrofuturistic apparati.

Skeletons, medical artifacts, and other obscure and precious treasures all displayed in a wooden pharmacist's cabinet.

An unusual number plate signifies the building's saucy past.

Weird wax anatomical models reside here, as do other anatomical specimens.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

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

The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

The headless bodies of more than 1,300 guillotined victims of the Reign of Terror are buried here in mass graves.

One of the oldest masonic museums in Paris.

A unrivaled and rather horrifying collection of wax dermatological models.

Saintly bones pressed into a wax effigy of a Catholic superstar.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

The first green space constructed on an elevated viaduct.

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 of magic with a Sadist past.