This paper aims to offer a contribution to the debate on urban security starting from the assumption developed in the Introduction that the fall of the communist regimes, the end of the Cold War, and the ongoing globalization processes produced a rescaling of authorities, bringing cities back to the centre of the political universe, and to the fore in the competition for the control of coercive resources. In other terms, cities return to be the privileged spaces of mediation between actors that are main players both at the local level and in the globalization processes; and, as a consequence, inside cities, violence turns out to be a fundamental mediator. This evolution is offering violent non-state actors (VNSAs) unprecedented opportunities to compete for the control of the territory, dictating to social sciences a redefinition of the very concept of urban security. The first section of the paper draws on the foam theory to outline a model of analysis of the urban spaces; the second section debates the securitization strategies conceived in the past decades, starting from the USA; the third section is intended to attune foam theory with the concept of urban resilience to violence. Finally, the Conclusion adumbrates the advent of a campus architecture, capable of planning spaces suitable for new and alternative forms of urban sociality.