Urban visions for the architectural project of public space

Public spaces should be places that support an intense civic life. They have been so throughout history, even if in each culture and historical period they have taken very different shapes and followed different design principles. Nevertheless, during the XX century, the Modern Movement faced some difficulties in dealing with public spaces. Too many times the zoning approach opposed the complexity, mix of uses and intensity required by lively public spaces, where social encounters and knowledge exchanges are made possible. In the XXI century, public spaces regained a major role in city projects and urban strategies all over the world. Their appearance was enriched by new forms. Besides the traditional squares, parks and promenades of compact cities, new metropolitan open spaces and collective places related to transport network nodes emerged. This paper focuses on the urban design of such contemporary collective places. Based on an overview of the historical evolution of public spaces, we identify some design principles (from the overlap of scales to acupuncture strategies, through to the complexity of relations between urban architectures) necessary to ensure that metropolitan nodes emerge as places full of urbanity rather than as deserted non places.