The first green space constructed on an elevated viaduct.

The narrowest street in Paris.

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

The video game-themed street art first popped up in the French city.

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

France's national museum of scientific and industrial instruments.

The history of radiation is on safe display at the foot of a radiation science laboratory.

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

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

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

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

The Sun King's military models, saved from the Louvre.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

This statue was given to France by the United States to commemorate the centennial of the French Revolution.