The Iron Curtain dividing East and West Germany (and the Eastern Bloc) from the West was completed in 1952. However, there was a gap - in Berlin, where they was freedom of movememt between East and West Berlin. At the Potsdam Conference in 1945 it had been agreed that Berlin was to adminstered as a whole by the four Allies. Of course, with the emergence of the Cold War this became impossible. Refugees and migrants of every kind poured through this gap, and East Germany was rapidly losing skilled people. In 1961 the East German government, in consultation with the Soviet government, built the Berlin Wall, in order to halt migration out of East Germany. It was of course an admission of failure. The Berlin Wall came to have a symbolic and emotional significance that went well beyond its actual importance.