Six residential areas of the interwar Berlin Modern Style have been given in 2008 the status as UNESCO World Heritage Sites. In respect to its architecture and city planning, Berlin of the 1920s was considered the "avant-garde center of the world". These world-class projects have had an enduring effect on the definition and spread of social housing. This volume documents these six residential areas, using various historical and current photo material, plans and maps. The relevant historical turning points are explained in order to aid the readers understanding of the extraordinary importance of these sites for the worldwide culture of structure and its environment in the 20th Century.