Tickets for a range of boat trips from Cala Gonone to the beaches and deep grottoes that pit the shore are sold at the port. Most famous of the grottoes is the Grotta del Bue Marino, formerly home to a colony of Mediterranean monk seals, or “sea ox”. It’s among Sardinia’s most spectacular caves, a luminescent gallery filled with remarkable natural sculptures, resembling organ pipes, wedding cakes and even human heads – one of them is known as Dante, after a fondly imagined resemblance to the poet. Trips here cost around €20 including entry to the grotto. Other sea excursions provide access to various beaches along the coast, the most popular of which are Cala Luna and Cala Sisine – for more solitude, opt for one of the remoter swimming and snorkeling stops.