By 1900, Germany was the dominant power on the European continent and its rapidly expanding industry had surpassed Britain's while provoking it in a naval arms race. Germany led the Central Powers in World War I (1914–1918) against France, the United Kingdom, Russia, (by 1915) Italy and (by 1917) the United States. Defeated and partly occupied, Germany was forced to pay war reparations by the Treaty of Versailles and was stripped of its colonies as well as of home territory to be ceded to Belgium, France, and Poland, and was banned from uniting with German-settled regions of Austria. The German Revolution of 1918–19 put an end to the federal constitutional monarchy, which resulted in the establishment of the Weimar Republic, an unstable parliamentary democracy. In the early 1930s, the worldwide Great Depression hit Germany hard, as unemployment soared and people lost confidence in the government. In January 1933, Adolf Hitler was appointed Chancellor of Germany. His Nazi Party quickly established a totalitarian regime, and Nazi Germany made increasingly aggressive territorial demands, threatening war if they were not met. Remilitarization of the Rhineland came in 1936, then annexation of Austria in the "Anschluss" and German-speaking regions of Czechoslovakia with the Munich Agreement in 1938, and further territory of Czechoslovakia in 1939. On 1 September 1939, Germany initiated World War II in Europe with the invasion of Poland. After forming a pact with the Soviet Union in 1939, Hitler and Stalin divided Eastern Europe. After a "Phoney War" in spring 1940, German forces swiftly conquered Denmark, Norway, Belgium, Luxembourg, the Netherlands, and France, and forced the British army out of Western Europe. In 1941, Hitler's army invaded Yugoslavia, Greece and the Soviet Union.