Catacombs of San Gennaro — Wikipedia

The Catacombs of San Gennaro are underground paleo-Christian burial and worship sites in Naples, Italy, carved out of tuff, a porous stone. They are situated in the northern part of the city, on the slope leading up to Capodimonte, consisting of two levels, San Gennaro Superiore, and San Gennaro Inferiore. The catacombs lie under the Rione Sanità neighborhood of Naples, sometimes called the "Valley of the Dead". The site is now easily identified by the large church of Madre del Buon Consiglio.