Bulgarian Stara Planina Mountain range, eastern Europe. It extends east to west across central Bulgaria from the Yugoslav border to the Black Sea; the highest point is Botev Peak, at 7,793 ft (2,375 m). The range forms the major divide between the Danube River in the north and the Maritsa River in the south. It is crossed by about 20 passes (notably Shipka Pass), several railway lines, and the Iskur River