Naours, France

Located in the northern part of France, the ancient underground city of Naours is another complex labyrinth of more than 300 rooms. Originally used as a quarry, it soon became a hidden village underneath because of the obvious reasons of refuge and defense.

Dating back to the third century AD, it once had wells, chapels, and stables. But also enough room for approximately 3,000 people. The modest beginnings of this subterranean settlement date back to the 2nd century, during the reign of the Roman Empire.

During those days, the location was nothing more than a limestone quarry. Still, for the following centuries, the citizens in the area transformed it into a hiding place and an underground storage facility in times of war and invasions during the Middle Ages.