Grotta di Nereo (Cueva de Nereo)

Reckoned to be the largest underwater cave in the Mediterranean. It opens in the limestone cliffs of Capo Caccia, about 100 m north of the famous Neptune's Grotto. The cliff falls vertically to some thirty metres, where the deepest entrance lies; there are further mouths at 18 and 16 m. It is possible to follow a complete ring through the interior, passing through wide chambers with walls covered in red coral, an ascending tunnel into a hall lit from outside and a broad passage with a white sand floor that returns to the starting point, exiting through a window at around 18 m.