Among the motifs represented on the walls of the prisons of the Holy Office in Palermo and other places of seclusion and detention are biblical scenes, figures of saints and martyrs, of Christ and the Madonna. Religious iconography can be found in the artistic expressions of prisoners of all times and places, as in Mexican Chicano mural art, in which traditional sacred images such as the Virgin of Guadalupe take on a strong political and identity connotation. Starting from the history of the panopticon and an analysis of prison space in the Middle Ages, to William Kentridge’s ‘political’ frieze in Rome, in this week we explore the votive dimension of graffiti and the role of muralism as political activism, social criticism and a tool of protest and resistance. Case studies from different historical and geographical contexts (from Italy to Spain, from Germany to Turkey, from Mexico to Chile) offer the opportunity to reflect on the relationship between punishment and expiation, faith and devotion, art and dictatorship, freedom and censorship, concealment and visibility as well as on the question of the (im)permanence of graffiti and the intrinsic fragility of a medium entrusted with the task of preserving and handing down memory.