The submerged Park of Gaiola forms the core of the Posillipo coastline, between the cliffs of the Trentaremi bay and the slopes of Marechiaro, covered with Mediterranean scrub. Within the park, the integral reserve area includes the stretch of sea facing the Posillipo promontory and the islets of Gaiola, while the general reserve area includes the remaining stretch within the perimeter of the park itself. The underwater landscape consists of a mixture of marine populations, favored by the water circulation system in the gulf, and the remains of archaeological structures: harbor basins, nymphaea, and fishponds, currently submerged due to the slow sinking of the Earth's crust (bradyseism), related to the above Villa of Vedio Pollione.