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

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

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.

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

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

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

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

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

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

This museum houses an imposing skeleton army comprised of creatures great and small.

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

A museum of magic with a Sadist past.

France's national museum of scientific and industrial instruments.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

Paris' linguistic guide to the international language of, yes, love.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

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

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