Tremiti Islands represent for Gargano National Park a real casket between the sky and the sea, rich in landscape treasures, historical memories, and natural monuments. Most of the south-eastern slope of San Domino holm is ideal to carry out walks rich in interesting observation occasions. For our itineraries, we have chosen the stretch between Cala del Sale and Grotta delle Viole, a particularly charming route of 500 meters. After a stretch on foot, the tour will continue by boat and there will be a diving opportunity to admire the wonderful seabed. Along these trails, visitors will discover some of the most characteristic species of photophilic algae biocenosis.