Divers who enjoy caves should visit the ones at the foot of the calcareous cliff of Capo Caccia, near Alghero.
The whole area is famous for its underwater caves (the Cave of Nettuno), that extend for hundreds of metres in tunnels and hollows of karst origin.
The Cave of Nereo is the most famous and the biggest underwater cave in Europe. It extends for over 300 m in longitude. It is almost 10 m high.
You can also dive in the Cave of Faco, Cave of Punta Giglio, Cave of Sommergibile or Madonnina, or take the opportunity to gaze into the deep blue of the famous Portico of Punta Semaforo.
It is important to remember that expert local guides, good torches and Ariadne's thread are the basic safety requirements for people who want to venture into the endless hollows of this area.