Public space in cities is in crisis. The symbolic elements constructed in public spaces in the past no longer serve to represent the flows circulating through them. According to the Dialogue Collective Public Space: New Perspectives, organized by the Universal Forum of Cultures, Barcelona 2004, the progressive weakening of public space has two underlying causes: the weakening of the political dimension of the city and the fact that the very notion of shared urban life is going through a deep crisis. We need a profound change in cities and local management. This change should reorient the thinking of city planners and political representatives, focusing on the city as a place of exchange that embraces new forms of institutional interaction and unconstrained relationships between citizens. Public urban space has a key role to play in the development and integration of cities. This paper presents the experience of some projects, named Luzboa, where art (culture and the creative arts) and light (science and technology) were used to promote urban development and to revitalize public space. Luzboa was a pioneer project in Portugal, built at the intersection between economic (science and technology innovation) and socio-cultural trends (culture and arts), with the support of public and private capital. Luzboa was 2 weeks of light-art animation in Lisbon's streets, conferences and workshops. More than 30 works brought live experience of the night to citizens and visitors in the old part of the city. In this paper, under inspection are: the new agendas for urban development; the reorientation of urban planning to focus on developing an active, cultural city, rather than simply highlighting historical heritage; the question of finance for innovation and creative activity; the management of knowledge and the role of various intermediaries.
