The document summarizes the partitioning of Berlin following World War 2. Germany was divided into four occupied zones, including Berlin. Over time, the Soviets tried to drive out Western allies from Berlin, leading to the Berlin Airlift and later the building of the Berlin Wall in 1961 to stop East Germans from fleeing to the West. The wall divided the city until 1989 when reforms led East Germany to open its borders and the wall fell, reunifying Berlin.