Going Underground. Making Heritage Sustainable

The experience of the COST action CA18110 “Underground Built Heritage as Catalyser for Community Valorisation” is pointing out the need to improve the current means, methods, policies, and practice for producing a balanced and sustainable approach to Underground Built Heritage conservation and promotion. This Special Issue focuses on two main research fields. The first is concentrated on holistic approaches to UBH conservation and re-use, while the second on the introduction in the cultural heritage of the paradigm of living labs, based on co-creation, co-development and co-management. This Special Issue aims to value the underground space as a depository of local identity and history, placing its cultural component as a catalyst for a broader strategy of community engagement and regeneration policies. The overarching idea is to reverse the current sectoral planning literature approach, which considers only the spatial value of the underground, as an affordable solution for locating new urban functions and saving surface space for urban development. To that end, this Special Issue aimed at stimulating multidisciplinary papers and the cross-fertilization of knowledge among scientists (i.e., historians, architects, engineers, archaeologists, planners, geologists, etc.), practitioners, public officials, and technicians, such interdisciplinary initiatives being rather limited in the field of underground space. This issue supported the introduction of tools, suitable for both neighborhood and district planning level and for single UBH interventions, very flexible for upscaling and easily replicable in different social, economic, and cultural urban regeneration contexts, characterised by different underground sites, local service demand, touristic potential, legal frameworks, and stakeholders. Finally, it had the purpose of collecting specific case studies on UBH, with urban or rural regeneration interventions, or introducing experiences of sustainable tourism and creative entrepreneurship. The 13 papers investigate interaction mechanisms among the various actors involved, such as public institutions, private stakeholders, and local communities, and advance understanding, from both a theoretical and practical point of view, of the policy conditions allowing the conservation and valorisation of UBH sites. In particular, some papers propose innovative approaches for developing trust and transparency among different stakeholders, public and private, global and local, and how to integrate heritage aspects into sectoral policies. Only transparent and integrated policies will make it possible to achieve a collaborative approach with authorities responsible for restoration and conservation, especially in the case of new functions for an underground artefact. As demonstrated by many success stories, UBH added-value increases when combined with objectives from other policies, such as spatial policy, water, energy or transport.