The Germans attacked the Soviet Union (now Russia and 14 independent states) with the largest army in history. Nazi Germany quickly took western Russia, laid siege to Leningrad and Moscow and occupied the Crimea. However they were stopped dead by Russian winter. Scorched earth policy caused roads, railways and food production to be destroyed. As a result, German soldiers died of hypothermia (death by freezing). With the Germans struggling, the Russians fought back and in the winter of 1942, the Germans were defeated at Stalingrad (Volgograd). The summer of 1943 saw victory for the Russians at the Battle of Kursk. The Siege of Leningrad was raised and by the spring of 1944, the Soviets regained Crimea. Following this, the Soviets began to liberate Eastern Europe.