The urgent challenge is to develop new tools, methods and forms of intervention at multiple scales from the domestic to the territorial scale, from public space to infrastructural networks, from activism to institutional roles, redefining architecture’s disciplinary territories as a system of knowledge production and action. The Seoul Architecture and Urbanism Biennale (SBAU) 2019 claims architecture as an active participant in the construction of the city and as an agent in realizing a political and cultural project for the city. SBAU 2019 aims to create a space of research and debate opened to and engaged with a truly global audience. The Biennale will explore the condition of the collective in the city, not as the natural state of the city today, but rather as a condition to be reclaimed and reframed, suggesting that the collective subject is in fact the instrument of political action and transformation of the city. This biennale is an incitement to demonstrate and evidence what collective space can mean, how we can imagine it as an agent of political action of both of social, spatial and environmental justice in order to speculate on the new city. It is a platform to grapple with essential and necessary disciplinary and cultural transformations that must take place to enable us to answer these challenges and to understand how new collective practices can be mapped, tested, innovated and leveraged to truly gain agency and relevancy.