The island of Capri is located in the Gulf of Naples, located in front of the peninsula. The island is, unlike the neighbouring Ischia and Procida, karst. Initially it was combined with the Sorrento peninsula, then submerged in the sea and separeted from land, where today lies the small mouth. Capri has a complex morphological structure, with peaks of medium height (Monte Solaro 589 m and Monte Tiberio 334 m) and vast Interior Highlands, including the main one is called "Anacapri". The coastline is indented with numerous coves and bays alternating with steep cliffs. The caves, hidden beneath the cliffs, were used in Roman times as nymphs of the sumptuous villas which were built here during the Empire. The most famous is undoubtedly the Blue Grotto, magical lighting effects that were described by many writers and poets. Characteristic of Capri are the famous Faraglioni, three small rocky islets a short distance from the shore, creating a spectacular visual effect.