Let's CROWD will overcome challenges preventing the effective implementation of the European Security Model with regards to mass gatherings. This will be achieved by providing a dynamic risk assessment methodology for the protection of crowds during mass gatherings, a policy making toolkit for long-term and strategic decision making of security Policy makers, and a set of human centered tools for law enforcement agencies (LEAs), including real time crowd behaviour forecasting, innovative communication procedures, semantic intelligence applied to social networks and the internet, and novel computer vision techniques.