The europe's second longest river forms a border between romania and before it drains into the sea.

The Europe's second longest river Danube, forms a border between Romania and Ukraine, before it drains into the Black Sea.

The Danube is the second longest river in Europe. It passes through or touches the territory of ten countries. It starts its flow from Germany's Black Forest, in the southern part of the country, and it ends up in the Black Sea. Before it drains into the Black Sea, the Danube forms a natural, but also a political border between the East European countries of Romania and Ukraine.