Lebensraum (German pronunciation: [ˈleːbənsˌʁaʊm] , lit. 'living space') is a German concept of expansionism and Völkisch nationalism, the philosophy and policies of which were common to German politics from the 1890s to the 1940s. First popularized around 1901, Lebensraum became a geopolitical goal of the German Empire in World War I (1914–1918), as the core element of the Septemberprogramm of territorial expansion. The most extreme form of this ideology was promoted and initiated by the Nazi Party, that had ruled Nazi Germany, whose ultimate goal of which was to establish a Greater German Reich. Lebensraum was a leading motivation of Nazi Germany to initiate World War II, and it would continue this policy until the end of the conflict.
Following Adolf Hitler's rise to power, Lebensraum became an ideological principle of Nazism and provided justification for the German territorial expansion into Central and Eastern Europe. The Nazi policy Generalplan Ost (lit. 'Master Plan for the East') was based on its tenets. It stipulated that Germany required a Lebensraum necessary for its survival and that most of the populations of Central and Eastern Europe would have to be removed permanently (either through mass deportation to Siberia, extermination, or enslavement), including Polish, Ukrainian, Russian, Belarusian, Czech, and other Slavic nations considered non-Aryan. The Nazi government aimed at repopulating these lands with Germanic colonists in the name of Lebensraum during and following World War II. Entire populations were ravaged by starvation; any agricultural surplus was used to feed Germany. The Jewish population was to be exterminated outright.