St Nicholas’ Fortress, located in Croatia, Šibenik, at the entrance to the St Anthony’s Channel, as a unique construction of the Venetian Renaissance fortification architecture, represents a monument of world heritage in the Mediterranean. The fortress is the only Venetian military fortification completely surrounded by the sea. It was built in the 16th century on the islet of Ljuljevac at the site of the former Benedictine Monastery of St Nicholas, from which it took its name.