This large, circular tomb is the final resting place of the first emperor of Rome.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This ancient market is often referred to as the oldest shopping mall in the world.

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

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

The middle finger of modernity.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

Once a safe haven for locals engaged in blood feuds, this 400-year-old fortified tower is now a museum showing what life was like for those lying in wait within its walls.

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

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

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

The former global standard for the exact mass of one kilogram sits under lock and key outside Paris.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

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

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

The oldest continuously operating mint in the world that has been making coins since the 9th-century.

The approximate spot where the last Grand Master of the Knights Templar was put to death.

Indents in the pavement are all that remain from a grisly death machine in Paris.

This upscale streetwear store is hidden behind a fake Snapple machine in the back of a deli.

A museum of magic with a Sadist past.

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

This banal Parisian entranceway is not what it seems.

France's national museum of scientific and industrial instruments.

The world's most remote permanent settlement on an active volcano.