Danube
The Danube was once a long-standing frontier of the Roman Empire, and today flows through 10 countries, more than any other river in the world. Originating in Germany, the Danube flows southeast for , passing through or bordering Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine before draining into the Black Sea. Its drainage basin extends into nine more countries. The Danube river basin is home to fish species such as pike, zander, huchen, Wels catfish, burbot and tench. It is also home to a large diversity of carp and sturgeon, as well as salmon and trout. A few species of euryhaline fish, such as European seabass, mullet, and eel, inhabit the Danube delta and the lower portion of the river.
Nazi rule over the Danube River
Before World War II, international trade and commerce at the mouths of the Danube River, as well as many of the physical works needed to keep vessels from running aground, were regulated by an international agency called the European Commission of the Danube, founded in 1856. By the time the Hitlerian invasions began in 1938 the commission was composed of the riparian (river-bordering) states, plus France, Great Britain, and Italy, the chief commercial nations of Europe at that time. Above Brăila, the river was under the control of the International Danube Commission, a body composed only of the riparian states.