(especially for returning ). From mid–1940, the ethnic cleansing (forcible removal) of Poles from the initially occurred across the border, to the General Government (a colonial political entity ostensibly autonomous of the Reich); then, after the invasion of the USSR, the displaced Polish populations were jailed in (Pole-storage camps) in Silesia and sent to villages designated as ghettoes. In four years of Germanisation (1940–44), the Nazis forcibly removed some 50,000 ethnic Poles from the Polish territories annexed to the Greater German , notably some 18,000–20,000 ethnic Poles from Żywiec County, in Polish Silesia, effected in Action Saybusch. The Nazi invasion of Poland consisted of atrocities committed against Polish men, women, and children. The German population's psychological acceptance of the atrocities was achieved with Nazi propaganda (print, radio, cinema), a key factor behind the manufactured consent that justified German brutality towards civilians; by continually manipulating the national psychology, the Nazis convinced the German people to believe that Slavs and Jews were Untermenschen. For example, leaders of the Hitler Youth were issued pamphlets (such as On the German People and its Territory) meant to influence the rank-and-file Hitler Youth about the necessity of Nazi racist practices in obtaining for the German people. Likewise, in the proper, schoolchildren were given propaganda pamphlets (such as You and Your People) explaining the importance of for the future of Germany and the German people. East–West frontier Concerning the geographic extent of the Greater Germanic , Adolf Hitler rejected the Ural Mountains as an adequate eastern border for Germany, arguing that such mid-sized mountains would not suffice as the boundary between the "European and Asiatic worlds", and that only a living wall of racially pure Aryans would suffice as a border. He also advocated that permanent war in the East would "preserve the vitality of the race": In 1941, the Reich decided that within two decades, by the year 1961, Poland would have been emptied of Poles and re-populated with ethnic-German colonists from Bukovina, Eastern Galicia, and Volhynia. The ruthless Germanisation that Hitler enacted for was attested in the reports of (soldier–peasant) colonists assigned to ethnically-cleansed Poland—of finding half-eaten meals on the table and unmade beds in the houses given them by the Nazis. Baltic Germans from Estonia and Latvia were evaluated for racial purity; those classified to the highest category, , were resettled in the Eastern Wall. Moreover, the Germanisation of Russia which began with Operation