This exhibition presents the outcomes of two academic years (2023–24 and 2024–25) of study, research, and design work developed within RRR Lab (Integrated Design Studio for Architecture and the Built Environment – University of Trieste), focused on the theme of the European Capitals of Culture (ECOC), With particular attention to the case study of Gorizia–Nova Gorica 2025. The exhibition traces the evolution of a design journey articulated through seminars, workshops, study days, architectural, urban and landscape projects, installations, and thematic displays developed for the two cities — a unique cross-border urban system that has served as a real experimental ground for design-led inquiry. Over the past years, Gorizia and Nova Gorica have prepared for the major cultural event of 2025. Now that the event is underway, the design reflection shifts towards the "after": What happens once GO!2025 officially ends? The notion of “before” and “after” has informed all the works displayed, emphasizing the role of time in design across different scales and dimensions. Time, process, phased reasoning, and transformation — understood as spatial and biodynamic evolution — have been the conceptual and operative foundation of the projects exhibited. Ephemeral interventions as vectors of present-day change and the trace as a tool for post-event reflection guided both studio cycles: “Gorizia / Nova-Gorica Felix” (a.y. 2023–24) and “L’éphémère est éternel” (a.y. 2024–25). The exhibition is organized into thematic sections (the archipelago), reassembling a wide range of materials developed by around fifty students and ten faculty Teachers and Researchers from the University of Trieste, in collaboration with Local Institutions (GECT / EZTS GO - European Grouping of Territorial Cooperation, OAPPC-GO - Chamber of Architects, Planners, Landscape Architects and Conservators of Gorizia, Chamber of Engineers of Gorizia) and Public Administrations (Municipality of Gorizia). One section also presents the broader scientific and cultural activities that contributed to shaping the vision of the city-as-event.