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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

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

A popular shrine where the Blessed Virgin allegedly appeared in 1830, displaying a holy armchair and two incorruptible remains of Lady Saints.

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

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

A curious collection of locks and keys.

A font of vintage porn on the silver screen.

Inside a former cabaret, seven floors of erotic art.

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

This Parisian café is dedicated to great tea and the art of knitting.

Claude Monet was baptized in this lavishly ornate Paris church.

The narrowest street in Paris.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

What looks like a normal building is really a hollow facade hiding a subway vent.

A French artist's vague warning hangs over Belleville.

This bridge was constructed from the rubble of the infamous Bastille.

The oldest and smallest cemetery in Paris is only open to the public twice a year.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

BDSM, 1930s Style.

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

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

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