In view of the ongoing globalization and structural changes, it is important fort he city oft he 21 st century to develop strategic visions and ideas for ist future design. Due to the multiple crises in the areas of food, energy, climate, finance, economy social affairs and politics, previous strategies for sustainable development are reaching their limits. Terms such as land recycling, efficient land use, urban densification, structural change and especially sustainability on an ecological, economic ans social level are being used to describe these challenges.