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

Noirish green neon marks the location of one of the oldest private detective agencies in France.

An off-the-beaten-path boutique stuffed with an eclectic collection of upcycled goods.

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

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

One of the last umbrella repair shops in Paris upholds the nostalgic art of umbrella making.

A unrivaled and rather horrifying collection of wax dermatological models.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

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.

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

The first green space constructed on an elevated viaduct.

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

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

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

The history of radiation is on safe display at the foot of a radiation science laboratory.

Statue of death tucked in the University of Medicine courtyard.

A subterranean shelter remains intact under a busy Paris railway station.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

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

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

Indents in the pavement are all that remain from a grisly death machine in Paris.

A surrealist timepiece by the artist of melting clocks.

A museum of magic with a Sadist past.

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