The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

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

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

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

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

The first green space constructed on an elevated viaduct.

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

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

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

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

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

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

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

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

A mechanized clock where a man fights off a dragon, crab, and rooster.

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

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

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

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

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The oldest stone house in Paris was built by its most famous alchemist.

This massive library holds what was once the largest book collection in the world.