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

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

Despite being considered a thoroughly American sport, basketball's oldest surviving playing field is found in the basement of a Paris YMCA.

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.

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

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

Statue of death tucked in the University of Medicine courtyard.

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

A surrealist timepiece by the artist of melting clocks.

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

France's national museum of scientific and industrial instruments.

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

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

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

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

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

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

The celebrated eyesore created by starry-eyed sweethearts.

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