The ‘Renaissance of the City’ is celebrated, especially in Berlin - a city shaped by its unique history and its recent search for a new urban identity. Since German reunification, Berlin has turned again - as popular media often picture it - into one of the most vibrant and lively cities in Europe. But what makes a city a city? Cities are often described as dense, diverse and dynamic. Is it as simple as that? During the Summer School 2010 we want to explore the phenomenon of “city-making” both in theory and practice. The leitmotif of the two-week course will be the assumption that Berlin is not one city, but lots of cities constituted by various fragments, partly interwoven and partly polarised in its social, historical, political, economical and formal dimensions. Therein small spaces are marked as particular environments. From different academic perspectives we will introduce various concepts of city and we will get to know governing instruments as well as experience social and architectural realities. The focus of this undertaking is the particular structure of the city of Berlin and its new and less manifest demarcation lines more than twenty years after German reunification. With the participation of professors, researchers, and urban activists, the course will integrate different concepts of what makes a city a city. Readings, site visits as well as interviews with stakeholders will support lectures and debates.