to Soviet Ukraine, where they were accepted, and participated in the advancement of Ukrainian science and culture. This period was cut short when Joseph Stalin became the leader of the USSR following Lenin's death. Stalin did away with the NEP in what became known as the Great Break. Starting from the late 1920s and now with a centrally planned economy, Soviet Ukraine took part in an industrialisation scheme which quadrupled its industrial output during the 1930s. However, as a consequence of Stalin's new policy, the Ukrainian peasantry suffered from the programme of collectivization of agricultural crops. Collectivization was part of the first five-year plan and was enforced by regular troops and the secret police known as Cheka. Those who resisted were arrested and deported to gulags and work camps. As members of the collective farms were sometimes not allowed to receive any grain until unrealistic quotas were met, millions starved to death in a famine known as the Holodomor or the "Great Famine", which was recognized by some countries as an act of genocide perpetrated by Joseph Stalin and other Soviet notables. Following on the Russian Civil War, and collectivisation, the Great Purge, while killing Stalin's perceived political enemies, resulted in a profound loss of a new generation of Ukrainian intelligentsia, known today as the Executed Renaissance. World War II Following the Invasion of Poland in September 1939, German and Soviet troops divided the territory of Poland. Thus, Eastern Galicia and Volhynia with their Ukrainian population became part of Ukraine. For the first time in history, the nation was united. Further territorial gains were secured in 1940, when the Ukrainian SSR incorporated the northern and southern districts of Bessarabia, Northern Bukovina, and the Hertsa region from the territories the USSR forced Romania to cede, though it handed over the western part of the Moldavian Autonomous Soviet Socialist Republic to the newly created Moldavian SSR. These territorial gains of the USSR were internationally recognized by the Paris peace treaties of 1947. German armies invaded the Soviet Union on 22 June 1941, initiating nearly four years of total war. The Axis initially advanced against desperate but unsuccessful efforts of the Red Army. In the battle of Kyiv, the city was acclaimed as a "Hero City", because of its fierce resistance. More than 600,000 Soviet soldiers (or one-quarter of the Soviet Western Front) were killed or taken captive there, with many suffering severe