One woman's decades-long obsession with the "La Fée Verte."

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

Abandoned railway line circling the city of Paris.

A mud statue stands in the dark tunnels, seeming to hold up the weight of the city above.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

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

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

The first green space constructed on an elevated viaduct.

This 18th-century sundial was designed to calculate the date of Easter each year.

An unusual number plate signifies the building's saucy past.

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

The video game-themed street art first popped up in the French city.

This banal Parisian entranceway is not what it seems.

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

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

The narrowest street in Paris.

Notorious artist squat renovated into legal studios.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.