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

A font of vintage porn on the silver screen.

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

An all-American grocery store in Paris sells U.S. "cuisine" like Pop-Tarts and Heinz ketchup to homesick ex-pats.

How did a French journalist’s grave become the sexiest statue in the cemetery?

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

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

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

The curious underground history of keeping Paris clean.

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

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

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

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.

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

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

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

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

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

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

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

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