The POSSOO project consists of a necessary recalibration of the center of Halle, both in terms of ecology and social amenities. The canvas of the project is the unearthing and renaturalization of the Zenne river, allowing for a new park landscape between the historical core of Halle and the Canal Brussels-Charleroi. Within this green lung, charged with open air sports facilities, a contemporary sports center complements the existing context. The former sports center (1972) with its intriguing wood structure will be reprogrammed as an evolutive parking infrastructure and mixer building. With POSSOO the city of Halle, together with the Flemish Environment Company (VMM), provides a precursing pilot project on the levels of mobility, city center activation, green and blue ecology as well as social empowerment.