Naples Underground

Naples is built on yellow tuff, a soft volcanic stone that is easy to cut and strong once exposed to air, and for two and a half thousand years Neapolitans have been digging into it. The Greeks quarried it to build Neapolis; the Romans turned the cavities into a network of cisterns fed by aqueduct channels that supplied the city with water until the late nineteenth century; and during the Second World War the same chambers became air-raid shelters where thousands of people sheltered from bombing. Napoli Sotterranea, entered from Piazza San Gaetano on Via dei Tribunali in the heart of the historic centre, is the best-known way to see this hidden city. A guide leads you down a long staircase to about forty metres below street level, through vast echoing cisterns, past the graffiti and objects left by wartime shelterers, and into a small modern experiment where plants are grown underground. The most memorable moment for many is optional: a passage through a narrow channel only a shoulder's width wide, lit by candle, which brings you out at a still, clear pool of water in an old cistern. Above ground again, the tour continues into a nearby basso — the street-level one-room homes typical of old Naples — where a trapdoor and a moved wardrobe reveal the remains of the Greco-Roman theatre of Neapolis, the same theatre where the emperor Nero is said to have performed. It is part archaeology, part social history, part theatre, and wholly Neapolitan.

Tours run frequently through the day in Italian and English, last about an hour and a half, and leave from the entrance at Piazza San Gaetano; skip-the-line tickets with the guided tour are available through Tiqets, which also sells combinations with the catacombs and the Archaeological Museum. The site is open daily, with longer hours at weekends. The descent involves well over a hundred steps each way, the temperature underground stays cool and fairly constant year-round (a light layer helps in summer), and the humidity is high. The narrow candlelit passage is optional and can be skipped by anyone with claustrophobia or a larger frame; guides wait for everyone at the other end. Wheelchair access is not possible, and the tour is not suitable for very young children who cannot manage the stairs.

Alternatives and add-ons: Naples has several other underground experiences worth knowing. The Galleria Borbonica, entered near Piazza del Plebiscito and Chiaia, follows a tunnel built for a Bourbon king's escape route and later used as a shelter and car pound, with vintage vehicles still inside; the Spanish Quarters have their own underground tour; and the complex of San Lorenzo Maggiore on Via dei Tribunali reveals a Roman market street beneath a Gothic church, a fine self-guided alternative for those who prefer not to go deep. Each shows a different layer of the city.

Because it starts on Via dei Tribunali, Naples Underground fits perfectly into a historic-centre day. Do the tour mid-morning, emerge for a pizza at one of the famous pizzerias nearby, walk the Christmas-crib workshops of San Gregorio Armeno around the corner, and continue along Spaccanapoli to the Sansevero Chapel. With teenagers it is often the highlight of the trip, and on a hot or rainy day it is the perfect retreat. The honest caveat: it is a popular, well-trodden tour, and groups can be large at peak times, so book an early slot if you want a more intimate visit and a guide who has time for questions.