The years of National Socialism are the darkest chapter in German history. Hitler's totalitarian regime permeated all areas of political, economic and social life. Mass media, cultural life and education were brought into line, extracurricular education was controlled through the Hitler Youth and BDM. Propaganda was the main means of power for the manipulation and mobilization of the German "people's community". At the core of the ideology of the Third Reich were the "Führerprinzip" and the unconditional cult around the person Hitler. Job creation measures such as the construction of the autobahn contributed to the recovery of the economy and increased Hitler's popularity, but only were intendend to serve the preparations for war. Critics and resistance fighters were hunted down by the Gestapo and SS terror organs. The barbarism of the Nazi tyranny culminated in the persecution and extermination of the Jewish population. Six million Jews lost their lives in the Holocaust. Germany occupied the Sudetenland and Czechoslovakia 1938 and 1939. The appeasement policy of the Western powers only was able to delay the war, not to prevent it. In his policy of aggressive expansion Hitler could not be pacified. Due to the civil mobilization, and finally the total economic and military armament, the campaign for conquest and extermination was prepared. On the 1st of September 1939, the German army invaded Poland, which led to the beginning of World War II.