As of September 2010 we (TU Delft) are going to work on an ambitious project about sustainable urban development to revive en energize old inner city areas of Rotterdam (notably, the old industrial port areas close to the centre). The challenge is to see how we can redevelop old and dense inner city areas to more sustainable, joyful and safer places… We are not only looking at how we can implement local renewable energy production, close energy loops and renegotiate public and private spaces in high density areas, but we are also trying the make big steps in low-carbon transportation and mobility. The challenge is to optimize both low-carbon living and moving, because these are so tightly connected, and to develop localized capabilities and infrastructures that support both these activity systems. Creating independent resilient low-carbon sub-systems within the city that are able to provide the energy for living and moving themselves. An experiment worth trying to create our future sustainable cities. Rotterdam offers a perfect context to work out these challenges and solutions could also work at other large dense port cities in this world.