The architecture of social housing was one of the major determinants of urban expansion in the 20th century. There is no single segment of architecture as well defined by social and sociological tides as public housing. Whether driven by socialist plans or capitalist subsidies, architects were always between the devil and the deep blue sea. One of the most open (read flexible) public housing concepts in Europe was the “IBA” in Berlin in the 80s, that is, before the fall of the Wall. At the time, Berlin emphasised two social features which together produced influential social-housing architecture. The first feature was openness as a political priority and sustained counteraction to the risk of infection posed by the Iron Curtain. The second feature was the remarkable social awareness maintained by the long presence of Willy Brandt and the SPD.