The Rhine-Main-Danube Canal (in German known as the Main-Donau-Kanal) is a canal that joins up the three rivers Rhine, Main and Danube so that boats can travel from one to the other. It is in Bavaria in the south of Germany. It goes from Bamberg, past Nuremberg, to Regensburg. It was finished in 1992. Boats can now travel from Rotterdam in the Netherlands all the way to the Black Sea. The canal is 171km (106 miles) long.
A previous "Ludwig Canal" connected the Danube to the Main from the middle 19th century until it was damaged in World War II and abandoned.
From Bamberg to Fürth the canal follows the valley of the Regnitz, a tributary of the Main. From Fuerth to beyond Roth it follows the valley of the Rednitz, a tributary of the Regnitz. It crosses the Frankish Alb mountains and joins the river Altmuehl near Dietfurt. From Dietfurt to Kelheim on the Danube the canal follows the Altmuehl valley.