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

A museum of magic with a Sadist past.

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

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

19th century pendulum and a clock restored by a rogue group of guerilla artists.

A surrealist timepiece by the artist of melting clocks.

Statue of death tucked in the University of Medicine courtyard.

Weird wax anatomical models reside here, as do other anatomical specimens.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

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

Where the high court feasted, frolicked, and high courtesans put their royal lovers' diamonds to the test.

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

The very center of Paris is surrounded by a bevy of strange good luck rituals.

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

A deep mark on the remains of a Roman temple, believed to be left by a legendary warrior.

Plaques on its facade commemorate the Tiber's most destructive deluges.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

A forgotten "city of water" underneath the famous Trevi district.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

A statue representing a lost Roman profession that was vandalized for centuries.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.