A simple plaque on the facade is the only reminder that the treaty ending the American Revolution was signed inside.

Marie Antoinette and Napoleon Bonaparte were fans of this 200-year-old French chocolatier.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

The narrowest street in Paris.

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

Noirish green neon marks the location of one of the oldest private detective agencies in France.

Executions were once held near this beautiful 18th-century fountain.

The location of this small park was once the site of an infamous public morgue.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

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

Abandoned railway line circling the city of Paris.

Order a boozy baba au rhum at the oldest patisserie in Paris.

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

A series of abstract, silly sculptures represent the works of a great modern classical composer.

This frog-themed restaurant was frequented by Picasso, Saint-Exupéry, and more.

This small red school was where Germany signed their surrender during WWII.

An image of the legendary saint stands in the shadow of a cathedral she liberated.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.

BDSM, 1930s Style.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

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

This small, ingenious cannon once helped regulate Parisian life.

Shop at the 200-year-old store where Julia Child stocked up on copper cookware.

For more than a century, revolutionary graffiti has marked the wall of a Parisian church.