Parco sommerso di Gaiola, Marine protected area in Posillipo, Italy

Parco Sommerso di Gaiola is a marine protected area along the Posillipo coast, covering about 42 hectares of seabed from Marechiaro to Trentaremi Bay. The site contains Mediterranean marine life and submerged archaeological structures that lie beneath the water.

A Roman aristocrat built the Pausilypon Imperial Villa along the coast in the first century BC, including a large theater structure. This ancient residential complex was later partially submerged by the sea and now forms part of the park's archaeological remains.

The park takes its name from the two Gaiola islets it surrounds, which lie a short distance off the Posillipo coast. The protected area runs from the small borgo of Marechiaro to the bay of Trentaremi. Guided visits use a boat with an underwater viewing window, and snorkelling and diving itineraries are also offered; the visitor centre at the CeRD, the park's research and science communication centre, hosts school and training activities.

The best way to explore the protected area is from the water, with boat tours and snorkeling being the primary options for viewing the underwater sites. You should bring appropriate water gear and be prepared for changing conditions, as water access depends on weather and season.

The seabed holds sunken Roman ports and fish ponds that gradually went underwater due to bradyseism, a slow sinking of the earth's crust. This geological process makes the area a rare place where ancient history and natural forces are visibly connected.