Using the example of the Slovak Republic as a post-communist country and its city of Banská Bystrica, this article deals with the dilapidated municipal cultural property which was transferred from the state to the municipalities after the fall of communism in 1989. The long period of disorganization and public administration reforms has left many municipalities with abandoned infrastructures that have not found a new role in the globalized economy. Non-profits often substitute the public sector, especially in the provision of public services where the public sector has a lack of financial and/or organizational capacities and no or very little experience to tackle a specific issue, e.g., handling the abandoned cultural objects that were left to rot. The aim of the article is to investigate the regeneration of the unused property initiated by NPOs. We use retrograde analysis to investigate the impact of social innovation on unused properties. We examine the historical trajectory of individual cases and show what results have been achieved by social innovations. Using multi-case studies and interviews with stakeholders of the non-profits involved, the role of non-profits in the restoration of dilapidated cultural property and its return to use by citizens is examined and conclusions are drawn: non-profits bring social innovations in improving the urban design by saving dilapidated historical and cultural objects.