This boundary is mainly Danube; and a in the South of Dobrogea a terrestrial border.
This is the boundary with Ukraine: mountains and the river Tisa.
The river Danube and the South Dobrogea.
the country that forms the northern boundary of the United States is Canada :)
Carpathian Mountain
This is the river Danube.
The sea that forms the northern boundary of Africa is the Mediterranean Sea. The countries of Morocco, Algeria, Tunisia, Libya and Egypt border it.
red river
The Arctic Ocean
The sea that forms the northern boundary of Africa is the Mediterranean Sea. The countries of Morocco, Algeria, Tunisia, Libya and Egypt border it.
Mediterranean Sea
soviet union