The FOR:UM was created as part of Zukunftsstadt Dresden 3.0 and under the auspices of Team Zirkuläres Bauen (bau&wesen e.V.). The aim was to design and construct a mobile, circular micro-architecture for joint activities and events in public spaces. After completion, it is now available to Dresden initiatives for collective use and has become our mobile operations center. The FOR:UM accommodates a variety of uses and creates temporary interaction spaces for neighborly encounters and exchange. The modular structure allows it to be adapted to different usage formats (e.g. exhibitions, cooking events, podium...). A good practice example for the successful closing of urban material cycles has been created, in which approaches from cooperative urban development are combined with alternative construction processes. At the same time, FOR:UM is a mobile material library that makes cycles visible in public spaces.