iver Krka springs in the west base of the Dinara Mountin, not far from Knin, and after 72 km flows into the sea near Šibenik. The area of the middle and lower basin of Krka river was proclaimed protected in 1985. The northern borders of the national park are medieval fortresses Trošenj i Nečvan, constructed in the 14th century. Down the river from the fortresses, there is Roški waterfall, 27 meters high. Between Roški waterfall and another sight, Skradinski buk, there is the Lake Visovačko, named after the small island of Visovac, located in the lake. The end of Skradinski buk is the beginning of the Krka’s entering the sea. Prukljansko lake and the canyon behind the lake are rich with shells: 57 species of shells live here.