Rhineland (rĪnˈlăndˌ) [key], Ger. Rheinland, region of W Germany, along the Rhine River. The term is sometimes used to designate only the former Rhine Province of Prussia, but in its general meaning it also includes the Rhenish Palatinate, Rhenish and S Hesse, and W Baden. (For a description, see Rhine.) Cologne, Mainz, and Ludwigshafen are among the chief cities. The Treaty of Versailles (1919) after World War I provided for the Allied occupation of most of the region; the Ruhr district was occupied by French and Belgian forces from 1923 to 1925. Largely as a result of the efforts of the German foreign minister, Gustav Stresemann, the last occupation troops (who were French) withdrew from the Rhineland in June, 1930, five years before the terminal date set by the treaty. The Treaty of Versailles had also provided that after Germany recovered the occupied territories, it was to maintain no fortifications on the left bank of the Rhine and within a zone extending 31 mi (50 km) E of the Rhine. Germany specifically reaffirmed those conditions in the Locarno Pact of 1925. In Mar., 1936, however, the National Socialist (Nazi) government of Germany began to remilitarize the Rhineland, and at the same time Hitler denounced the Locarno Pact. The League of Nations censured Germany, but took no further action. The German fortifications in the Rhineland—the so-called Siegfried Line—were an extensive system of defenses in depth, which were penetrated by the Allies in World War II only after very heavy fighting. The Rhineland was the scene of the Rhenish separatist movement, whose leaders staged uprisings in Düsseldorf, Bonn, Koblenz, Wiesbaden, and Mainz, and proclaimed a Rhineland republic at Aachen in 1923; the movement, however, collapsed in 1924.