Naples Underground (Napoli Sotterranea)

Beneath Naples lies a labyrinth carved over 2,400 years. The Greeks quarried the soft yellow tufa here from the 4th century BC to build the city above; the Romans extended the cavities into a vast aqueduct system that supplied Naples until a cholera epidemic in 1885. During World War II, these tunnels 40 metres down became air-raid shelters where tens of thousands of Neapolitans sheltered from Allied bombing—the graffiti, toys, and improvised homes of those terrified nights survive. In late September 1943, Naples rose against the German occupiers in the 'Four Days of Naples,' becoming the first Italian city to liberate itself before the Allies arrived. The underground preserves an unbroken timeline from antiquity to the war.