Underground Naples: catacombs, tunnels and the city you don’t see

Naples is a city that lives on many levels. On the surface there is the fascinating chaos of its alleyways, the scent of coffee, the sea, the baroque piazzas and that relentless energy that makes this Campanian city unique in the world. But beneath the streets, beneath the palaces and even beneath the churches, there is another city: silent, carved in tuff and full of mysteries.

The Neapolitan subsoil tells over two thousand years of uninterrupted history: from the Greeks, who in the 4th century BC quarried blocks of tuff to build the walls of Neapolis, to the Romans, who transformed those quarries into a sophisticated aqueduct, through to the Bourbons, who dug secret tunnels to provide the royal family with an escape route, and to the Neapolitans of the Second World War, who took shelter there during the bombings.

Visiting these places does not simply mean walking through tunnels and passages, but seeing Naples from a completely different perspective — coming into contact with the deepest memory of the city. An experience that is just as rewarding as any day spent above ground  — and in some moments surpasses it.

Here are the unmissable sites in the underground of Naples.

Napoli Sotterranea

Napoli Sotterranea is probably the most famous underground site in the city. A dense and complex network of tunnels, cavities and spaces that represents one of the most distinctive and fascinating heritage sites in all of Naples. It extends beneath the entire historic centre and is bound up with myths and legends that remain vivid in the collective imagination of Neapolitans today.

The galleries, initially excavated to extract the tuff needed to build the city, were later used as an aqueduct and then as an air-raid shelter during the Second World War. Along the route it is possible to see graffiti, personal testimonies and everyday objects that tell of underground life in another era. The visit includes the War Museum, the Hypogeal Gardens, the Greco-Roman Theatre and other spaces that reveal the historical layering of Naples in its most tangible form.

Galleria Borbonica

The Galleria Borbonica extends beneath the Pizzofalcone hill, near the Royal Palace, in the San Ferdinando district. By royal decree of 19 February 1853, Ferdinand II — King of the Two Sicilies — commissioned architect Errico Alvino to build an underground viaduct connecting Largo della Reggia with Piazza Vittoria. The official purpose was infrastructural, but the real one was military: to guarantee a safe escape route for the royal family in the event of civil unrest. After six years of construction, however, the king died and the project was left unfinished.

During the Second World War the spaces were used as air-raid shelters, then converted into a depot for impounded vehicles and salvaged materials — until an association reclaimed them and opened them to the public. Today several guided tours are available, designed for different levels of exploration and curiosity.

Catacombe di San Gennaro

Located beneath the Capodimonte hill, in the heart of the Rione Sanìtà, the Catacombs of San Gennaro are the most important early Christian monument in Naples. Dating back to the 2nd–3rd century AD, they became a pilgrimage destination in the 5th century, when the body of the city’s patron saint was interred here — his remains are now kept in the Crypt of the Cathedral, described in the article dedicated to the museums of Naples. The catacombs are arranged on two non-overlapping levels, both characterised by unusually large spaces compared to the more famous Roman catacombs.

Beyond their distinctive architectural structure, the complex stands out for its rich artistic heritage: pre-existing pagan elements from the 2nd century, mosaics and early Christian paintings, through to Byzantine frescoes from the 9th–10th century. Among the most precious works is the oldest known portrait of San Gennaro.

Catacombe di San Gaudioso

Still in the Rione Sanìà, a short distance from the Catacombs of San Gennaro, lie the lesser-known but equally fascinating Catacombs of San Gaudioso. Located beneath the Basilica di Santa Maria della Sanità, they take their name from Gaudiosus the African, a Tunisian bishop exiled by the Vandals and buried here between 451 and 453 AD.

The site brings together early Christian elements — the tomb of San Gaudioso, fine 5th–6th century frescoes and mosaics — and 17th-century noble burials, when the catacombs returned to use as a burial site. Of particular interest is a fresco of the Madonna believed to be the oldest depiction of the Virgin Mary in Campania. And for those with an interest in Neapolitan popular culture: it is said that a fresco in these catacombs inspired the great comedian Totò to write his celebrated poem “’A livella”.

Cimitero delle Fontanelle

The Cimitero delle Fontanelle is the symbolic home of the Neapolitan devotion to the dead — a devotion that for centuries has been intertwined with superstition, ritual and the most genuine form of affection. The site is an ancient tuff quarry carved into the Materdei hill, named Fontanelle after the streams of water that once flowed from the surrounding hillsides. It holds around eight million human skeletal remains.

Initially used to receive victims of the 1656 plague, it became the city’s main burial site during the cholera epidemic of 1837. Towards the end of the 19th century, the cult of the anime pezzentelle — the poor and abandoned souls — took root here. The faithful would adopt a skull, care for it and pray for the soul of the deceased in exchange for a blessing. Every corner is full of anecdotes, legends and curiosities waiting to be discovered.

Lapis Museum

Right in the historic centre, the Basilica of Santa Maria Maggiore in Pietrasanta — the first church in the city dedicated to the Virgin — conceals one of the most unusual and multidisciplinary underground itineraries in Naples, now known as the Lapis Museum. The route includes the crypt, with the remains of the ancient Temple of the goddess Diana and other significant archaeological features including opus reticulatum masonry, Hellenistic walls and a Roman mosaic floor. It continues through the Water Museum — the ancient Greco-Roman cisterns brought to life through light and colour installations that accentuate their volumes — and descends to the Sunken Decumanus forty metres below ground, the section of the aqueduct repurposed as an air-raid shelter during the Second World War. All enriched by evocative multimedia installations.

Neapolis Sotterrata

Beneath the Basilica di San Lorenzo Maggiore, just steps from Via San Gregorio Armeno, lies the underground itinerary known as Neapolis Sotterrata — an immersion into the city’s millennia-old history at around ten metres below street level, a stone’s throw from Vivaldo Suite Spaccanapoli. The archaeological area preserves the remains of the ancient Forum of Neapolis and represents one of the most important sites in the historic centre, both for its monumental value and its location within the Angevin complex of San Lorenzo Maggiore.

Among the most remarkable features is the macellum, the Roman market from the 1st century AD, consisting of a rectangular portico with shops looking onto a mosaic-paved courtyard with a central tholos used for selling food. One of the most vivid and concrete testimonies of everyday life in ancient Neapolis.

Practical tips for visiting underground Naples

Visiting the Neapolitan subsoil is an unforgettable experience, but a few tips will help you make the most of it — especially if you plan to combine it with a summer day in Naples, when temperatures above ground make the underground routes a particularly welcome refuge.

What to wear.  The underground maintains a constant temperature throughout the year, generally between 14 and 18°C. Even in the height of summer it is advisable to bring a light jumper or jacket. Comfortable shoes with non-slip soles are essential, as many routes include stairs, uneven surfaces and damp sections.

Book in advance.  Napoli Sotterranea, the Galleria Borbonica and the Catacombs of San Gennaro are among the most popular attractions in the city. Online booking is recommended and, on weekends and during high season, practically essential to avoid sold-out time slots.

Accessibility.  Not all routes are suitable for visitors with reduced mobility, as they often include narrow staircases, uneven passages and sloping environments. Some sites offer partially accessible routes: it is always worth checking the specific conditions of your chosen itinerary in advance.

Frequently asked questions about underground Naples

How long does it take to visit Napoli Sotterranea?

The standard guided tour of Napoli Sotterranea lasts approximately 80 minutes. Adding the Galleria Borbonica (standard route approximately 60–90 minutes) and the Catacombs of San Gennaro (approximately 50 minutes), you can easily plan a full day dedicated to the underground. Those with less time can choose one or two sites, with Napoli Sotterranea as the first choice for its central location and the variety of the route.

Is advance booking necessary?

Yes, especially for the most visited sites such as Napoli Sotterranea and the Catacombs of San Gennaro. In high season and on weekends, availability fills up quickly. Online booking is available on the official websites of each site and allows you to choose your time slot and the language of the guided tour.

Are the underground routes suitable for children?

Generally yes, but it depends on the age and sensibility of the child. Napoli Sotterranea and the Catacombs of San Gennaro are suitable even for young children, provided they are accompanied and with the awareness that these are dark, narrow in places and cool environments. The Cimitero delle Fontanelle, with its eight million skeletal remains, is more suited to older children. In any case, the presence of a guide makes the routes more accessible and engaging.

Which is the most evocative underground site in Naples?

It depends on what you are looking for. Those who want the most layered history and the most complete route will find Napoli Sotterranea unrivalled. Those fascinated by Bourbon history and secret tunnels will prefer the Galleria Borbonica. Those who love early Christian art will be struck by the Catacombs of San Gennaro. And those who want the most emotionally intense place — the one that best captures the Neapolitan relationship with death and the sacred — cannot miss the Cimitero delle Fontanelle.

Can you visit underground Naples independently, without a guide?

For most sites, a guided tour is compulsory or strongly recommended: the underground routes are complex and without a guide you would miss the historical details and the stories that make the experience truly memorable. Some sites also allow individual audio-guided visits. The Cimitero delle Fontanelle, on the other hand, can be visited freely and free of charge.