Apart from minor changes, the city boundary defined in the law is still the same as today, even though its character has changed several times over the years. Originally a mere municipal boundary, it became a demarcation line between occupation zones after 1945, a part of the Iron Curtain after 1949 with the Berlin Wall on some of its length between 1961 and 1990. Since the reunification of Germany it is the border between the German states of Berlin and Brandenburg.