The Danube River is the second longest river in Europe, and one of the principal transportation arteries on the continent. It is the only major European river to flow from west to east. It rises in the Black Forest region of Germany and flows in a generally easterly direction for a distance of about 2850 kilometers (1770 miles), emptying, on the Romanian coast, into the Black Sea. The delta of the Danube is a region of desolate marshes and swamps, broken by tree-covered elevations. The Danube is navigable by ocean vessels to Braila, Romania, and by river craft as far as Ulm in Germany, a distance of 2600 kilometers (1600 miles).