One of the oldest masonic museums in Paris.

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

A curious collection of locks and keys.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

A museum which takes visitors to the côté obscure of Paris.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

The floorboard scrawling of a tragic madman is on public display outside a Paris hospital, much to the dismay of its opponents.

This Paris art space celebrates the creativity and ingenuity that springs from abject poverty, especially in Africa.

The personal library of the founder of modern neurology is open to visitors.

BDSM, 1930s Style.

The Sun King's military models, saved from the Louvre.

The former home of France's controversial pop maestro is almost completely covered in ever-changing tributes and graffiti.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

This innocuous-seeming building is actually the remnant of a major wartime brothel.

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

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

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

Got apples?

This Parisian café sticks almost exclusively to an ethos of reuse.

This little-known relic crypt holds stolen parts of a Roman Empress.

This Parisian fountain is a little bit fantasy and a little bit nightclub.

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

A Belle Epoque bordello turned into a themed love hotel.

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