In this era of economic globalisation, multimedia communication and cross-border migration, cities increasingly consist of parallel worlds. Different urban cultures and practices immediately confront each other. Call centres, informal markets, sprawling communities, new diaspora and transitory lifestyles represent trans-national spaces in urban centres, whose cultural, economic and social activities are no longer confined to their localities. How do planning and architecture react when their central point of reference loses its clear nature and thus its identity? Using concrete examples, the Bauhaus Kolleg VI 2004/2005 examined these unique spatial shapes that emerge from the tensions and conflicts in the “trans-national city“, also in order to work out strategies for the problems faced by urban development and thus add a contribution to the ongoing international urban discussion.