Tuff stone quarry used for the 6th c. BC walls of Neapolis.
It was identified by chance in 1987 following subsidence under the Pianto cemetery below the square of the church of Santa Maria del Pianto. The quarry has horizontal ridges corresponding to the height of the blocks and, surprisingly, the characteristic alphabetical marks of the ancient quarrymen. From the quarry the blocks were transported to the city along the straight line of via Nuova Poggioreale to via Casanova to enter Naples from the ancient gate where Castel Capuano is now located.