The Danube Commission oversees navigation on the Danube River in accordance with the Danube Convention signed in Belgrad in 1948. The Convention provides for free navigation on the Danube in accordance with the interests and sovereign rights of the 11 Danubian States (Austria, Bulgaria, Croatia, Germany, Hungary, Moldova, Slovakia, Romania, Russia, Ukraine, Yugoslavia), and aims to strengthen the economic and cultural relations of the States among themselves and with other nations.
      In 1992 the Rhine-Main-Danube Canal between Nürnberg and Kelheim created a transeuropean waterway from Rotterdam to Sulina on the Black Sea. The yellow line marks the general course of the Rhine from the North Sea to its source in Germany, through the canal, and then the Danube East to the Black Sea.
     The souvenir sheet was issued by Yugoslavia in 1998 to mark the 50th anniversary of the Convention and the Commission.