Nazi Germany, officially the German Reich and later the Greater German Reich, was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a totalitarian dictatorship. The Third Reich, meaning "Third Realm" or "Third Empire", referred to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which the Nazis referred to as the Thousand-Year Reich, ended in May 1945, after 12 years, when the Allies defeated Germany and entered the capital, Berlin, ending World War II in Europe.
After Hitler was appointed Chancellor of Germany in 1933, the Nazi Party began to eliminate political opposition and consolidate power. A 1934 German referendum confirmed Hitler as sole Führer (leader). Power was centralised in Hitler's person, and his word became the highest law. The government was not a co-ordinated, cooperating body, but rather a collection of factions struggling to amass power. To address the Great Depression, the Nazis used heavy military spending, extensive public works projects, including the Autobahnen (motorways) and a massive secret rearmament program, forming the Wehrmacht (armed forces), all financed by deficit spending. The return to economic stability and end of mass unemployment boosted the regime's popularity. Hitler made increasingly aggressive territorial demands, seizing Austria in the Anschluss of 1938, and the Sudetenland region of Czechoslovakia. Germany signed a non-aggression pact with the Soviet Union and invaded Poland in 1939, launching World War II in Europe. In alliance with Fascist Italy and other Axis powers, Germany conquered most of Europe by 1940 and threatened Britain.