This paper introduces a methodology for resilience assessment of critical infrastructures based on massive data. The methodology is developed for the needs of the RESIIST research project. We start from the observation that the security of large cities has become a major issue. To ensure the proper functioning of critical infrastructures, it is essential to make the right decisions at the right time. To do this, managers are informed in their decision-making processes by several indicators such as resilience. As insecurity becomes more and more threatening with technological, natural and terrorist risks, it is essential to have an indicator of resilience of the infrastructures guaranteeing security. We therefore propose an innovative method of assessing resilience. It is innovative in that it combines both the genericity (it applies to all types of infrastructure), it takes into account several dimensions (economic, technical, social, human, regulatory etc.), it integrates massive data (from cameras, sensors, GIS, and social networks), it allows decision-making in an immersive environment in virtual reality.