Naples, Italy’s third-largest city and one of the oldest continuously populated urban areas in the world, has grappled with its fair share of international headline–grabbing troubles in recent chapters of its over-2,800-year history: a waste management crisis, mafia warfare, social inequity, and sinkholes so large that—somewhat ironically, considering the city’s infamous waste woes—garbage trucks have plunged into them.
While sinkholes aren’t a rarity across Italy, particularly southern Italy, a new report detailed the particular threat that they pose to the historic urban core of Naples, which was inscribed on the UNESCO World Heritage List in 1995. The bustling, bewitching heart of Naples, the largest historic city center in all of Europe, is populated by a wealth of centuries-old religious structures—cathedrals, chapels, and churches built in an array of architectural styles—numbering roughly 500 in total. As detailed in research published last month by the Journal of Cultural Heritage, 95 historic places of worship within Naples’s World Heritage Site zone are at risk of being damaged or destroyed by sinkholes caused by the collapse of underground cavities.
As described in the Art Newspaper, the center of Naples sits atop a vast and labyrinthine network of ancient subterranean spaces including catacombs, crypts, aqueducts, and cisterns. While the buildings and notoriously narrow streets that sit above the city’s tunnels and caves have largely held their ground, quite literally, over the centuries, the new findings from a team based at the Department of Earth, Environmental, and Resource Sciences at the University of Naples Federico II illustrated how vulnerable the landmark churches that compose a bulk of the real estate in Naples’s center are.
Using map data and satellite imagery that tracked small but important shifts in ground levels, the team created a citywide inventory of sinkholes, cavities, and places of worship and concluded that nine historic Naples churches are built directly above underground cavities and are at high risk of collapse. Another 57 places of worship are susceptible to “potential future cavity collapses” per the Art Newspaper.
Among the sinkhole-threatened churches are the San Giuseppe delle Scalze a Pontecorvo (1619), Basilica dello Spirito Santo (1775), Basilica di Santa Maria della Pazienza (1636), and the Pantheon-esque Basilica di San Francesco di Paola (1824), which is one of the most prominent ecclesiastical landmarks in the city as it flanks the western side of the main square of Naples, Piazza del Plebiscito. All of these churches are popular tourist attractions and/or active places of worship. As noted by the research team in its case study, titled Sinkholes Threatening Places of Worship in the Historic Center of Naples, these four sites and five others most at risk “require a quick response in terms of characterization, stability analysis, and real time monitoring.”
The research team noted that between 1870 and 2010, 190 sinkholes of varying sizes have been recorded in and around Naples, 25 percent of them being caused by underground cavity collapses triggered by heavy rainfall, human activity, and other factors. Included in that figure is a sinkhole that opened inside the church of San Carlo alle Mortelle in 2009. After nearly $1.8 million in repair work, the Baroque-style 17th-century church reopened in 2017 according to the Art Newspaper.