The Carpathians are separated from the Alps by the Danube. The two ranges meet at only one point: the Leitha Mountains at Bratislava. The river also separates them from the Balkan Mountains at Orşova in Romania. The valley of the March and Oder separates the Carpathians from the Silesian and Moravian chains, which belong to the middle wing of the great Central Mountain System of Europe. Unlike the other wings of the system, the Carpathians, which form the watershed between the northern seas and the Black Sea, are surrounded on all sides by plains, namely the Pannonian plain to the southwest, the Lower Danubian Plain to the south, with the southern part being in Bulgaria, and the northern - in (Romania), and the Galician plain to the northeast.