Photo by Iwan Baan   By its very nature, a city serves as an accelerator of integrated formulas of the circular economy. Citizens’ proximity, production activity, business networks, service suppliers, educational bodies and institutions, create an ideal platform to activate in a short time effective forms of collaboration and business model that complete the picture. The city acts as a hub for the movement of materials and services, offering diversified competences and, at the same time, customers sensitive to new experimentations. If seen as a tool to attract and reintroduce “nutrients” (whether they are technological, biological or natural), the city encompasses in a concentrated way all the key words of the circular economy: matter, service, ...