1. A major industrial and coal mining region in the valley of the Ruhr river in northwestern Germany; Also called: Ruhr Valley.
2. A tributary of the Rhine; Also called: Ruhr River.
River in Germany; it rises in the Rothaargebirge Mountains and flows W to join the Rhine at Duisburg. The Ruhr Valley (228 km/142 mi), a metropolitan industrial area (petrochemicals, automobiles, iron and steel at Duisburg and Dortmund), was formerly a coal-mining center.
The area was occupied by French and Belgian troops 1923–25 in an unsuccessful attempt to force Germany to pay reparations laid down in the Treaty of Versailles. During World War II the Ruhr district was severely bombed as it was vital to German industry. The seven dams across the river were constantly bombed by the Allies in an attempt to flood the area (e.g., with the “bouncing bombs”), although without success. Allied control of the area from 1945 came to an end with the establishment of the European Coal and Steel Community 1952.