PLACES Networks partners are developing a common platform for a wide and diverse community of actors to promote the cooperation in their science communication activities, at city/regional level. Over four years, 67 science communication institutions (science centres, museum, festivals) are supported to work with their local authority administrators and policy makers to plan and implement their long-term co-operation for the “city of scientific culture”. PLACES promotes the City of Scientific culture at regional levels via the ERRIN network, whose regional members host the most advanced “science cities” and at city level where ECSITE/EUSCEA science communicators have engaged their local authorities in the project, by creating a formal City Partnership (CP). The 3 PLACES partner networks (ECSITE/EUSCEA/ERRIN) create a cyber-platform for their selected members and organize many meetings merging the various types of actors and producing thematic reports and concrete recommendations. At the city level, members of ECSITE and EUSCEA receive support to produce a City Action Plan, a Local Survey and, if selected, a seed money grant to launch a new activity. Local and regional authority administrators receive training and support via the expertise of science communicators. An independent European team of academic researchers assesses the impact of activities in 10 science centres, 10 events and 10 cities, by selecting with neutrality among the PLACES participants (around 70 cities). The numerous operational links stimulated by PLACES will generate much new knowledge which will be used to define, at a European level, models and recommendations toward various political level. With PLACES a European community of professionals from 28 countries will share and exchange experiences and information around the dedicated cyber-platform OPEN to be maintained permanently as a new service of dissemination after the project completion.