In ancient Greece, the most important meaning of the term ‘polis' came to be ‘body of citizens'. Similarly, for Plato the best form of government was the one that led to the common good. Now, in the 21st century, when more than half of the world population is already living in cities and the share of urban population is projected to increase, especially in Africa and Asia, cities need to regain a holistic understanding of the common good and rethink themselves to be prepared for current and future impacts related to climate change, migration or safety, to cite just a few.
Fortunately, some are leading the way with stimulating proposals. Yet the challenges of a global world are still significant. In coping with them, we need a transdisciplinary approach enabling us to understand the leadership role of cities and their multiplicity of interacting systems, be they technical, financial or societal.Cities are hubs of innovation and knowledge, drivers of economic growth, prosperity, and social wellbeing."