This banal Parisian entranceway is not what it seems.

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

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

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

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

The Sun King's military models, saved from the Louvre.

Notorious artist squat renovated into legal studios.

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

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

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

This modest marker near Notre Dame identifies the very center of Paris.

The first green space constructed on an elevated viaduct.

The Argonaute submarine was the French navy's pride and joy in the 1950's.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

The celebrated eyesore created by starry-eyed sweethearts.

With a history of slaughter, feast, and famine, remnants of the pork industry decorate this area--even its church.

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.

A magical, macabre wax museum, beloved by locals, uses real artifacts to depict an assassination from the French Revolution.

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

Abandoned railway line circling the city of Paris.

A surrealist timepiece by the artist of melting clocks.

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

César Baldaccini's iconic sculpture of a 40-foot thumb stands tall in La Défense.

In this Parisian garden's grotesque former life as a zoo it fed exotic animals to the bourgeois and put humans on exhibit.