The historiography of armed movements in Colombia has mainly focused on analyzing guerrilla groups of the second half of the 20th century from a macro perspective, and offering structural explanations. Through employing tools such as the reduction of the scale of observation, interviews, oral history, and the analysis of biographical trajectories, the present study allows us to apprehend a complex, diverse guerrilla organization, with nuanced and conflicting experiences of its members, such as the 19th of April Movement (M-19). Through twelve life stories of these urban militants of Bogotá, who occupied medium and operative positions, each chapter will allow understanding their lived experiences, presented as partial similarities according to the way they joined the group and lived militancy and demobilization, as well as the multiple ways in which they understand their passage through the guerrilla, their positions in the social space, political identities, and relations with family, gender, and age. Due to its focus on biographical trajectories, this work is not only a study of the political world of the M-19 movement, but also of urban life in Bogotá in the 1970s and 1980s, including family lives, the phenomenon of displacement towards cities, the politicization of student movements, among other topics that appear concurrently in the course of the narration.