Introduction: Large urban agglomerations and mega-cities promise, on the one hand, significant potential for economic progress by creating innovative environments through connecting human capital, global actors as well as financial and information resources. But, on the other hand, these conditions pose significant risks at global, regional and local scales by aggravating social disorganization, economic disparity, loss of governability, and ecological stresses that create unhealthy local environments. Because of an increasing recognition that the future development of humankind concentrates in urban areas, there is a rapidly growing scientific interest in understanding the evolution of large agglomerations, their driving forces, consequences and potential solutions to their problems.Aim of the symposium: Taking up the global challenge of urbanization, the symposium provides the space for an interdisciplinary discussion on significant socio-economic, health and ecological consequences of continued future growth of agglomerations. It explores mitigation and steering strategies and actions. A particular concern is the interdependence between human behavior and vulnerable living conditions in densely populated areas.Content: In expectation that existing problems will further aggravate in future, there is an urgent need for research to develop concepts for the sustainable development of these areas and support their application. The understanding of the complexity of interrelated urban processes and mechanisms as a precondition is currently limited. There is likewise lack of knowledge on optimum strategies for an integrated management of the urban system. To work on these questions, research results and lessons from various international projects shall be presented und discussed in the symposium.