Naples · Italy
Naples Underground - Tunnels, Cisterns and Catacombs
Beneath the noise of Naples lies a second city, cut into soft volcanic stone over roughly 2,500 years. Here is why its tunnels, cisterns and catacombs exist and which ones you can visit.
Published September 30, 2026
Stand in Piazza San Gaetano and you hear scooters, church bells and someone shouting a pizza order. Walk down a flight of steps and it all stops. Naples underground is a second city, cut into soft yellow stone over roughly 2,500 years, with cisterns, quarries, burial galleries and air-raid shelters stacked beneath the streets.
The air turns cool. Your voice echoes. Here is why that hidden city exists, what Neapolitans used it for, and which parts you can visit between one espresso and the next.
Why does Naples have so many tunnels and cisterns?
Underground Naples is a network of cavities dug into tuff, a light volcanic rock that is soft enough to cut with hand tools and strong enough to build with. Greek settlers began quarrying it for their walls and temples, and Romans later extended the tunnels into an aqueduct system that fed hundreds of cisterns below the city. For centuries almost every palazzo drew its water from a well that reached down into this hidden reservoir.
The logic was neat. Every block of stone lifted out became a house above, and every hole left behind could hold water. Channels linked the cisterns, so the whole city sat on a kind of stone sponge.
Maintaining it took a special trade. The pozzari, the well-keepers, climbed through narrow shafts to clean the cisterns and could pop up inside private homes. Many locals connect them to the legend of the munaciello, a mischievous little monk who hides objects and leaves coins behind. Ask a Neapolitan about him. Most will smile, and few will say he isn't real.
What was the underground used for over the centuries?
The short answer is almost everything. Tuff quarries became cisterns, cisterns became storage rooms, and some caves became places of worship or burial long before anyone thought of tourism.
Early Christians carved catacombs into the hills north of the old walls. Later, whole quarries were filled with bones when the city ran out of burial space. In other spots the old aqueduct was sealed off after outbreaks of disease, and the cisterns were abandoned or filled with rubble.
Then people forgot. Entire chambers vanished from memory until speleologists and volunteers started clearing them, bucket by bucket. The full story is long and layered, and the [Napoli Sotterranea history pages](https://www.napolisotterranea.org/en/history/) trace it in more detail than any single visit can.
Which underground sites can you visit in Naples?
Four places give you a solid picture of Naples underground, each with its own mood.
Napoli Sotterranea starts in Piazza San Gaetano, in the heart of the historic centre. Guides lead you about 40 metres down into Greco-Roman cisterns and through tunnels so narrow you edge along sideways by candlelight. The tour also slips into an ordinary ground-floor flat, a basso, where a sliding bed reveals the remains of the Roman theatre. Visits are guided, and the [official Napoli Sotterranea site](https://www.napolisotterranea.org/en/) lists times and booking options.
The Catacombs of San Gennaro sit beside the Basilica of the Incoronata at Capodimonte. They are wide, airy and painted, with frescoes of early saints and the site where the city's patron was once buried. The smaller Catacombs of San Gaudioso lie under the church of Santa Maria della Sanità, where skulls set into the walls once had painted bodies below them. Both are run by a local cooperative, and the [catacombs' official website](https://catacombedinapoli.it/en/) covers tickets and access.
The Bourbon Tunnel, or Galleria Borbonica, was dug for a king who wanted an escape route from the Royal Palace to the barracks. Later it served as a shelter and then as a police depot, so you pass rusting cars and old scooters in the dark. Entry is from Vico del Grottone, near Piazza del Plebiscito, and the [Galleria Borbonica website](https://www.galleriaborbonica.com/) explains the different routes.
For something stranger, the Fontanelle Cemetery in the Sanità is a former quarry lined with thousands of skulls. Locals once adopted individual skulls, cleaning them and asking for favours. It is quiet, moving and unlike anywhere else, one of the city's more unusual hidden gems.
Most visits are guided, and some need booking in advance. Temperatures stay cool all year, and paths can be tight and uneven.
How did Neapolitans use the tunnels as shelters?
During the Second World War, Naples was one of the most heavily bombed cities in Italy, and its residents went underground. Old cisterns beneath the historic centre, including those on the Napoli Sotterranea route, were cleared and fitted with stairs, lights and latrines. The Bourbon Tunnel became a refuge for families from the Chiaia and Pallonetto neighbourhoods near the royal quarter. People slept, cooked and waited there through the raids, sometimes for days. They left traces behind. You can still see handwritten messages on the walls, children's toys, bed frames and simple household objects, which guides point out with care. These are not dramatic reconstructions but the ordinary things of ordinary lives, and they make the war feel close in a way a museum case rarely does. Standing among them, you understand that the tunnels were never just an engineering curiosity. They were the place where much of the city held its breath and survived.
It is a quieter part of any underground Naples tour. Take a moment there before you climb back into the light.
Can you combine underground Naples with the street-level city?
Yes, and it works best by area. Every entrance to the underground sits in a neighbourhood worth exploring on foot.
In the historic centre, pair Napoli Sotterranea with a walk down Spaccanapoli, the straight street that splits the old town in two. Duck into San Lorenzo Maggiore, browse the nativity workshops on Via San Gregorio Armeno, then stop for a pizza on Via dei Tribunali. Its crust feels even better after an hour in a cistern.
The Sanità neighbourhood, where the comedian Totò was born, links the catacombs and the Fontanelle. It is a lively, working quarter of market stalls, laundry lines and baroque staircases. Try a fiocco di neve, a cream-filled bun from a local bakery, between visits.
For the Bourbon Tunnel, come up and walk to Piazza del Plebiscito, then down to the waterfront at Via Partenope for views of Vesuvius. A coffee at a historic café nearby rounds it off nicely.
The rhythm is easy. One stop below, one stop above.
What should you know before going underground in Naples?
Going underground in Naples is easy to plan, but a few details make it much more comfortable. Book guided visits where the official sites require it, especially at weekends and in peak season.
Bring a light jacket, since the tunnels stay cool even in the heat of summer. Wear sturdy shoes with good grip. Floors can be damp, and some staircases are steep. Photo rules vary by site, so ask your guide before you raise your phone.
These visits suit rainy afternoons and the hottest days of the year especially well. If you have mobility concerns or dislike tight spaces, check each site first. The Catacombs of San Gennaro are largely step-free, while the candlelit passage at Napoli Sotterranea is optional and can be skipped.
Ready to plan your own route through Naples?
Create your own itinerary with Keptour: add the places that catch your eye, arrange them into days and share the plan with whoever is coming along. The more you look, the more layers Naples reveals. Go down, come back up, and let the city surprise you on every level.