The Sava is about 1000 km long. In Roman times, it was known as the Savus. It is often considered to mark the northern limit of the Balkans. The Sava has two main sources, both located in the alpine region of north-western Slovenia. The two arms of the Sava meet at Radovljica and the river takes the name Sava from this point. It is the border between Bosnia and Croatia. The navigation takes place across the plain of Vojvodina, a real bread-basket of Serbia with its mosaic of nationalities.