This paper describes and explains the very high and sustained levels of violence in Medellín, Colombia, over the last 20 years. Even within the turbulent context of Colombia, Medellín has experienced unusually severe violence, and several peace processes undertaken within the city have failed to provide more than temporary relief. The paper argues that this state of affairs has been the product of a “politicization of crime” in the city, a phenomenon that has been linked to global markets and a breakdown in the state’s provision of security. This failure of state provision created the opportunity for various insurgent and counter-insurgent forces to provide security themselves, thereby maintaining an uneasy truce with the authorities, commanding the allegiance of local communities, and establishing an urban base for their activities.