CELL is the association that promotes the Transition movement in Luxembourg. It brings together initiatives committed to social, ecological and economic change. CELL aims to make Luxembourg society less dependent on fossil energy, more supportive and able to respond better to climate change and the resulting challenges. CELL occupies Building 4 with its FUTURE (Forge for Tangible, Urban and Resilient Utopias) project. This project takes the form of a great outdoor esplanade known as a “piazza”. It will be built for and with the public, which will be able to develop it in accordance with the needs and desires of all. It has a vocation to host the Building 4 programme (concerts, workshops, citizens’ debates, and more) but also to develop awareness of ecological issues by prioritizing recycled materials in its construction and by regularly hosting teaching activities on the subject of sustainable development.