The Kajzer Park in Idrija (SLO) is a former mining site that is part of the UNESCO world heritage. The area around the exceptional building structure suffers from soil contamination. Idrija wants to seize the opportunity with the Territorial Agenda 2030 pilot to revitalise the outdoor spaces, open the area to the public and preserve heritage buildings while making the area more climate-resilient. Citizens will play a key part by engaging in planning and gardening activities. Additionally, the industrial area shall extend the biodiversity of the adjacent Upper Idrijca Landscape Park into the city. In the long-term, the experience with suitable flora shall be applied to other parts of the city with a “Green handbook” as a strategic approach.