Global climate change calls for rapid and decisive measures, particularly from the world's metropolises - the future of our climate will be decided in cities! But how can cities forge a path to a post-fossil fuel, post-atomic energy era, to ensure that urgently needed steps are put into practice?With the ENERGY ATLAS, the IBA Hamburg presents for the first time a spatialstrategic approach to the energetic conversion of a whole city district. Hamburg's Wilhelmsburg district serves as a demonstration area for intelligent urban development with regard to urgent energetic questions. The analytical methods used here form the basis for urban action strategies, which can be applied more generally, demonstrating impressively how cities in particular can become the pioneers of climate protection and resource conservation.