The rivers most navigated are the Rhine, Moselle, Main, Danube, Rhone, Saone, Seine and Rio Douro The Rhine River flows 820 miles to Rotterdam where it empties into the North Sea. The Main, 310 miles long, is now extended by the Main/ Danube Canal which links the Main to the Danube, with the Danube River, 1770 miles long flowing to the east, emptying into the Black Sea. The Saone and Rhone Rivers in south France, flow into the Mediterranean Sea, with the Saone now linked to the Moselle. The Seine River, in northern France, flows into the English Channel.