PurposeThe actual uses to which public art is put have been virtually ignored, leaving multifarious dynamics related to its esthetic encounters unexplored. Both audience agency in placemaking and sensemaking and the agentic role of place as more than a mere platform or stage dressing for transformation are routinely neglected. Such transformative dynamics are analyzed and interpreted in this study of the Derry–Londonderry Temple, a transient mega-installation orchestrated by bricoleur artist David Best and co-created by sectarian communities in 2015.Design/methodology/approachA range of ethnographic methods and supplemental netnography were employed in the investigation.FindingsParticipants inscribed expressions of their lived experience of trauma on the Temple's infrastructure, on wood scrap remnants or on personal artifacts dedicated for interment. These inscriptions and artifacts became objects of contemplation for all participants to consider and appreciate during visitation, affording sectarian citizens opportunity for empathic response to the plight of opposite numbers. Thousands engaged with the installation over the course of a week, registering sorrow, humility and awe in their interactions, experiencing powerful catharsis and creating temporary cross-community comity. The installation and the grief work animating it were introjected by co-creators as a virtual legacy of the engagement.Originality/valueThe originality of the study lies in its theorizing of the successful delivery of social systems therapy in an esthetic modality to communities traditionally hostile to one another. This sustained encounter is defined as traumaturgy. The sacrificial ritual of participatory public art becomes the medium through which temporary cross-community cohesion is achieved.