Massive limestone with vertical walls rich in air and sea caves. The cave of Neptune can be reached either from the Escala del Cabiròl or by motorboats from Alghero and / or Cala Dragunara, along Capo Galera and the island of Foradada. inside, environments rich in stalactites and stalagmites and a lake. The submerged cave of Nereo: in immersion you enter at a depth of both 18 and 32 meters and exit from another opening at fifteen, with a path of 350 meters between galleries and chambers. Other less famous caves, such as Giglio, Pozzo, Falco and the blue tunnel, which crosses the promontory between Cala della Barca and Cala Puntetta, allowing passage at low depths from one side to the other.