Ever since the beginning of the twentieth century, Medellin became an axis of industrial development, housing thousands of migrants. The city was forged through informal population processes, motivated by the attraction towards the so-called progress and new sources of employment. In the 1940's, the armed conflict in the countryside intensified, generating exile and an accelerated urban growth: cities became places of refuge. Since then Medellin has been growing under the logic of war-migration-urban colonization. A brief walkthrough of the urbanization process is made based on the reports of residents from five neighborhoods in the peripheries of Medellin, focusing on the dynamics of recent popular settlement, period 1970-2012. The following was confirmed: a) the urbanization of the peripheries was the result of resistance and popular organization, b) new socio-spatial identities were generated, c) new tensions and disputes arose, d) the peripheries were valued becoming the object of economic interest and the popular sectors are stripped of the territories they urbanized.