Naples Underground history: A timeline of events

4th century BCE

• The story of Naples Underground begins with the ancient Greeks, who quarried tuff (volcanic rock) to construct the city of Neapolis. This quarrying created vast cavities beneath the surface.
• Early Greek settlers used some of these cavities as cisterns to store rainwater, laying the groundwork for Naples' extensive underground infrastructure.

Insight: Many of the ancient structures and ruins seen today have layers of Hellenistic influences beneath them, from the foundations of public squares to the Greek Walls at Piazza Bellini.

1st century BCE – 4th century CE

The Romans transformed the underground into a sophisticated system of aqueducts and storage units, supplying fresh water to the city.

• Napoli Sotterranea at Piazza San Gaetano and the Spanish Quarters Underground were integral to the aqueduct network, with interconnected tunnels running beneath the city.
• Greco-Roman theater: Portions of the Theater of Emperor Nero were later incorporated into the underground, now accessible through Napoli Sotterranea.
• Neapolis Sotterrata: A thriving macellum (Roman marketplace) flourished at the site of a Greek agora (public square), reflecting the commercial vibrancy of ancient Neapolis.

In 305 CE, the patron Saint Gennaro of Naples was reportedly martyred during the persecution of Emperor Diocletian. Early nuclei of the Catacombs began to form.

5th–10th century CE

Decline of Roman infrastructure: Following the fall of the Empire, the aqueduct system fell into disrepair. However, parts of the underground remained in use for water storage and drainage.

Christian burial practices: The religion flourished and the underground began to serve as burial sites for early Christians.

• The Catacombs of Naples, especially those dedicated to San Gennaro and San Gaudioso, further developed during this period, serving as both burial spaces and places of worship.
• A Christian basilica is built over the ruins of the Neapolis Sotterrata, slowly transforming into the San Lorenzo Maggiore Monumental Complex.

15th–17th century

Urban expansion: During Spanish rule, the population of Naples grew rapidly, necessitating new water storage systems.

• A 16th-century nobleman named Cesare Carmignano commissioned a new aqueduct to accommodate the city’s swelling water demand.
• The Spanish Quarters Underground: Further developed as a network of cisterns and drainage channels to support the Spanish Quarters, a densely populated neighborhood.

18th–19th century

• Military and civic use: The underground was adapted for military and public purposes under Bourbon rule.
• The Bourbon Tunnel was built near the Spanish Quarters during the 1850s as an escape route for the Bourbon King Ferdinand II, who feared an uprising during a period of political unrest.

1939–1945

• Air-raid shelters: The tunnels sheltered thousands from bombings, offering safety amidst destruction.
• Daily life underground: Families set up makeshift homes with bunk beds, cooking stations, and hospitals.
• Artifacts: Preserved items like toys, ration cards, and graffiti provide a poignant glimpse into wartime survival.

Imagine the hum of quiet conversations, children playing softly, and the constant fear above ground as families waited out bombings. Sites like Napoli Sotterranea and the Spanish Quarters Underground, which became makeshift sanctuaries, capture these memories vividly.

Families set up temporary living spaces deep below the surface, equipped with bunk beds, cooking stations, and even small hospitals. Personal artifacts such as ration cards, children’s toys, and faded propaganda posters remain preserved today, serving as a poignant reminder of Neapolitan resilience.

Late-20th century

• Archaeological efforts: Many underground sites were rediscovered and excavated in the decades after WWII, bringing Naples' hidden history to light. Enzo Albertini leads exploratory walks starting from the 1970s.
• Napoli Sotterranea officially opened to the public in 1985. Excavations under San Lorenzo Maggiore revealed Neapolis Sotterrata, the Roman marketplace beneath the church.
• The Catacombs of San Gennaro and San Gaudioso were restored and opened to the public in 1989, highlighting their importance as early Christian burial sites.
• In 1995, the Historic Centre of Naples was designated a UNESCO World Heritage Site. Napoli Sotterranea, which forms a vital part of this neighborhood, became a major tourist destination showcasing Naples' ingenious infrastructure and history.

21st century

• The underground sites of Naples have become iconic attractions, offering visitors a glimpse into the city’s layered history through regular guided tours.
• Above Neapolis Sotterrata ruins, the Monumental Complex of San Lorenzo Maggiore’s cloister now houses a museum and several halls showcasing the unique history of the site.
• In 2015, Napoli Sotterranea opened its innovative Hypogeum Gardens to experiment with crop growth in extreme conditions 40+ meters below the surface.