Here once reigned “sea oxen”, as the locals used to call monk seals due to their tapered shape and tame behaviour like that of an ox. These magnificent mammals, now (maybe) extinct, gave their name to a marvel of nature: the Sea Oxen Grottoes (Grotte del Bue marino), since the 50’s one of the main attractions of the Gulf of Orosei, in particular in Cala Gonone, in the Dorgali territory. Today they are a favourite destination among nature lovers, and the ideal union between sea and mountain: they are part of the karstic system Codula di Luna, Italy’s largest, seventy kilometres of tunnels in the bowels of Gennargentu.