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

A modern-day Lascaux cave underneath Paris.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

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

This surreal statue brings a famous French novel about a supernatural cad to arresting life.

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

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

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

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

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

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

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

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

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

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

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

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

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

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.

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

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

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

A surrealist timepiece by the artist of melting clocks.