European Infrastructure on Big Data and Social Data Mining - SoBigData: a research infrastructure (RI) providing an integrated ecosystem for ethic-sensitive scientific discoveries and advanced applications of social data mining on the various dimensions of social life recorded by ‚Äúbig data‚Äù. The research community will use the SoBigData RI facilities as a ‚Äúsecure digital wind-tunnel‚Äù for large social analysis and simulation experiments aimed at monitoring and what-if reasoning on policy stress test and decision support. SoBigData will serve the wide cross-disciplinary community of data scientists, i.e., researchers studying all aspects of societal complexity from a data- and model-driven perspective, including data miners, computer scientists, socio-economic scientists, network scientists, political scientists, human scientists, and more. The RI will provide the common ground for many H2020 projects aimed at tackling societal challenges like demographic change and well-being,  secure, Clean and Efficient Energy, Smart, Green and Integrated Transport, Europe in changing World.