The fortress of Tureta is the most significant fortress on the islands of Kornati, dating from the Byzantine period. It is located on the island of Kornat and probably dates from the 8th century.
It is assumed that the fortress was built up for military purposes (for protecting and controlling the navigation in this part of the Adriatic Sea). The defensive wall situated on Oštrica peninsula near Grebaštica is also very important. It was constructed in the 15th century.