Why did we choose agriculture as one of the four entry points to design Brussels’ ecosystems transition? The reasons are theoretical and contextual. Agriculture, through its multifunctional contribution to urban needs, is a potential sustainability hotspot. But it is also a challenge for Brussels, a city-region with very little agricultural land and facing a growth in population. This chapter presents some elements of an exploration of unconventional agriculture1 that led to the emergence of a project horizon for the Brussels Ecosystems MasterClass: the need to structure it spatio-environmentally and socio-economically, i.e. to design it as an ecosystem.