Isla Grosa Nature · San Javier, Mar Menor, Murcia Island of volcanic origin located in the Mediterranean, 2.5 kilometres from the northern end of La Manga, within the municipality of San Javier. With 17.5 hectares and more than 90 metres in altitude, it forms an eroded volcanic cone on which columnar joints can be seen in its southern cliffs. Beneath its waters lies the largest Posidonia seagrass meadow on the Murcian coast, and on land it stands out for its rich birdlife: it hosts the world's third-largest colony of Audouin's gull, a threatened species, as well as yellow-legged gull, European storm petrel, European shag and peregrine falcon. Protected as a natural park, ZEPA (Special Protection Area for Birds) and LIC (Site of Community Importance), Phoenician and Roman shipwrecks have been found in its waters, including a 5th-century BC Phoenician ship. Photo: Sauropodo (CC BY-SA 3.0) What to see and do in San Javier