City.Risks is a 3-year project funded by the H2020 programme. The project started in May 2015 and its main objective is to increase the perception of security of citizens in urban areas by activating in a more transparent and sustainable way their participation in communities, through which information and interventions can be provided both to proactively protect citizens from falling victims to criminal activities as well as to reactively provide more timely and effective response and assistance. In order to do so, the City.Risks project will leverage a set of innovative technologies, city infrastructures, and available data sources but, more importantly, will aim at making citizens' smartphones the modern tool for increasing their personal and collective sense of security. The project will design and develop an innovative ecosystem of mobile services that will transform citizens' smartphone and tablet into a tool to collect, visualise and share safety-critical information with the appropriate authorities and communities. The project will rely on a wide spectrum of available technologies to design and implement an interactive framework including authorities and citizens, through mobile applications that will allow to prevent or mitigate the impact of crime incidents or other security threats in a collaborative way. Thus, it will contribute to an increase of the citizens' perception of security, which will be measured and validated in real-life scenarios and conditions through the deployment and operation of pilot trials in several selected cities.