The River Sava is approximately 1000 km long. In Roman times it was called the River Savus. It is often considered as the northern limit of the Balkans. The River Sava has two main sources, both located in the mountainous region in north-western Slovenia. The two branches of the river merge together at Radovljica, from which point onwards it is known as the River Sava. The river is the natural boundary between Bosnia and Croatia. Navigating the river takes you across the Plain of Vojvodina, the natural bread basket of Serbia and a multi-ethic mix with inhabitants of some 26 different ethnic groups.