Introduction to the Underground City of Naples: Underground in Naples are a series of caves and buildings formed by hundreds of years of mining. Its history can be traced back to 5,000 years ago, and it underwent great development during the Greco-Roman era 2,000 years ago. After being abandoned, it became a ready-made garbage dump for Neapolitans and was used as a shelter during World War II. The Naples Underground City (Napoli Sotterranea) is located in the tuff rock formations beneath the city of Naples. It is a cave maze about 80 kilometers long. The atmosphere of the ancient ruins in the cave is in sharp contrast to the modern city above the ground, witnessing the city's The blending of the sacred and the profane.