The hydrographic map of Germany is dominated by just four major drainage systems: the Danube (in orange) in the south, the Rhine (in blue) in the west, the Elbe (in purple) in the east and the Weser (in green) between the latter two. In Antiquity, the Rhine was the border between the Roman Empire and the Germans. Rome once attempted to shift the border to the Elbe, which would have radically altered the course of history, but it suffered a massive defeat in 9 CE at the Teutoburger Wald (roughly between both rivers). Image: Grasshopper Geography
{}