This time, they were not rehabilitated. As Cold War tensions rose still further during the 1950s, restrictions were placed on travel between the Soviet sector (East Berlin) and the western sectors (West Berlin). For the second time in its history, the Potsdam Gate (or what remained of it), was like a dividing line between two different worlds. Lying on this invisible frontier, Potsdamer Platz was no longer an important destination for Berliners. Similarly, neither East Berlin nor West Berlin regarded their half as a priority area for redevelopment, seeking instead to distance themselves from the traditional heart of the city and develop two new centres for themselves, well away from the troubled border zone. West Berlin inevitably chose the Kurfürstendamm and the area around the Kaiser Wilhelm Memorial Church, while East Berlin built up Alexanderplatz and turned Frankfurter Allee (which they renamed Stalinallee in 1949, Karl-Marx-Allee in 1961), into their own showpiece boulevard. Potsdamer Platz, meanwhile, was more or less left to rot, as one by one the ruined buildings were cleared away, neither side having the will to repair or replace them. On the western side things did improve with the development of the Cultural Forum, whose site roughly equates with the former Millionaires' Quarter. The Berlin Wall With the construction of the Berlin Wall on 13 August 1961, along the intracity frontier, Potsdamer Platz now found itself physically divided in two. What had once been a busy intersection had become totally desolate. With the clearance of most of the remaining bomb-damaged buildings on both sides (on the eastern side, this was done chiefly to give border guards a clear view of would-be escapees and an uninterrupted line of fire), little was left in an area of dozens of hectares. Further demolitions occurred up until 1976 when the Haus Vaterland finally disappeared. After that, only two buildings in the immediate vicinity of Potsdamer Platz still stood – one complete, the other in a half-ruined fragmented form: the Weinhaus Huth's steel skeleton had enabled the building to withstand the pounding of World War II virtually undamaged, and it stood out starkly amid a great levelled wasteland, although now occupied only by groups of squatters. A short distance away stood portions of the former Hotel Esplanade, including the Kaisersaal, used at various times as a much scaled-down hotel, cinema, nightclub and occasional film-set (scenes from Cabaret were shot there). Apart from