"European Green Belt" linking national parks and nature reserves along the course of the old Iron Curtain from the Arctic Circle to the Black Sea. Museums and memorials along the old border commemorate the division and reunification of Germany and, in some places, preserve elements of the fortifications. Development of the inner German border Origins The inner German border originated from the Second World War Allies' plans to divide a defeated Germany into occupation zones. The boundaries between these zones were drawn along the territorial boundaries of 19th-century German states and provinces that had largely disappeared with the unification of Germany in 1871. Three zones were agreed on, each covering roughly a third of Germany's territories: a British zone in the north-west, an American zone in the south and a Soviet zone in the East. France was later given a zone in the far west of Germany, carved out of the British and American zones. The division of Germany was put into effect on 1 July 1945. Because of the unexpectedly rapid Allied advances through central Germany in the final weeks of the war, British and American troops occupied large areas of territory that had been assigned to the Soviet zone of occupation. The redeployment of Western troops prompted many Germans to flee to the West to escape the Russians' takeover of the remainder of the Soviet zone. The wartime Allies initially worked together under the auspices of the Allied Control Council (ACC) for Germany. Cooperation between the Western Allies and the Soviets ultimately broke down because of disagreements over Germany's political and economic future. In May 1949, the three western occupation zones were merged to form the Federal Republic of Germany (FRG) with a freely elected government. The Soviet zone became the German Democratic Republic (GDR), under communist rule. From the outset, West Germany and the Allies rejected East Germany's legitimacy. The creation of East Germany was deemed a Communist/Soviet fait accompli, without a freely or fairly elected government. West Germany regarded German citizenship and rights as applying equally to East and West German citizens. An East German who escaped or was released to the West was automatically granted West German rights, including residence and the right to work; West German laws were deemed to be applicable in the East. East Germans thus had a powerful incentive to move to the West, where they would enjoy greater freedom and