Rapid urban development in the second half of the 20th century led to increasingly urbanized structures. As a result, industrial areas that were previously located on the periphery have found themselves in the inner city areas, contributing to the deterioration of the environmental quality and the attractiveness of these areas. Their closure requires the revitalization of decayed areas. The aim of this paper is to present parks built in post-industrial areas in the context of the need to preserve the post-industrial heritage and place-based identity, and to improve the environmental and climatic values of cities. The study’s methodology consists of literature studies, in-situ field research and the use of geo-information systems. Based on an analysis and a detailed comparative study of selected projects carried out in Paris, Barcelona and Turin over the last forty years, the authors demonstrated that brownfield sites are transformed into green parks for leisure and recreation, forming part of the green-blue infrastructure of cities. They improve the environmental conditions of congested city centres, which is particularly important in the face of rapid climate change. The use of decayed brownfield sites for the redevelopment of high and medium-height greenery can help to reduce the urban heat island effect and air pollution. The struggle for a clean environment can be fought using natural structures, with greenery in parks and gardens becoming a tool for improving the climate and increasing urban water retention.