The cave is commonly called Grotta di Matermania but is also known as Grotta del Matrimonio or Matromania. It is a cavity about 30 meters long and 20 meters wide, with an average height of 10 meters.
Near the tower, in a crack in the ground, you can go down to the Grotta di Minerva or delle Sirene, where it is said that Partenope found refuge here …