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.
Internationalization of the Danube River
The Danube River has been a trade waterway for centuries, but with the rise of international borders and the jealousies of national states, commerce and shipping has often been hampered for narrow reasons. In addition, natural features of the river, most notably the sanding of the delta, has often hampered international trade. For these reasons, diplomats over the decades have worked to internationalize the Danube River in an attempt to allow commerce to flow as smoothly as possible.
Rivalry among the great powers — particularly Great Britain and Russia — hindered such cooperation, but in 1856, at the end of the Crimean War, and it was finally decided to establish an international organization where they all could work together on behalf of the Danube.