The attic of a four-century-old canal house hides a clandestine church.

The history and future of cannabis.

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

An odd museum dedicated to French fakes.

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

The largest medical and anatomical collection in France lies hidden from the public.

Abandoned railway line circling the city of Paris.

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

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Inside a former cabaret, seven floors of erotic art.

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

Notorious artist squat renovated into legal studios.

Dolls of all shapes and sizes display the eras of femininity in this spooky and beautiful collection.

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

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.

Pitié-Salpêtrière was the dumping grounds for women who received the dreaded diagnosis of "hysterical."

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

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

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

A popular shrine where the Blessed Virgin allegedly appeared in 1830, displaying a holy armchair and two incorruptible remains of Lady Saints.

A museum of carnival attractions where you are invited to ride the rides.

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