Naples undergound is a quarry from where the Greeks in the 4th century took blocks to build the city walls, Now it is a tourist attraction.
Ton Koene/© Ton Koene
Naples is a tale of two cities. Underground lies a 450 kilometer labyrinth of chambers and tunnels dating back to the 4th century B.C.E., formed when the Greeks extracted tufa stone to build ancient Neapolis. The Romans incorporated the tunnels into the city’s water system, which remained in use until the 1884 cholera epidemic, and they were later used as air-raid shelters during World War II. Guided tours are fascinating, but beware: The tunnels are narrow and dark, so they’re not for claustrophobics.