The Dutch city of Nijmegen was facing a number of major choices in housing and spatial planning. Each option represented major investments, take years to realise, and would shape the city for the coming decades. To bring a broad range of expertise to bear on these decisions and ensure that policies would work in the light of future uncertainties, a participatory scenario planning project was initiated. A total of 31 city representatives participated in five sessions, constructing scenarios and testing policy measures. Participants brought together over 300 ideas on future trends and developments. Clustering and rating these for uncertainty and importance points to two central trends. One major trend was individualisation versus cohesion. It is impossible to tell whether the Dutch society will become more individualistic or more inclusive in the future, yet this has major consequences for many municipal policy domains. A second important and uncertain development concerns knowledge institutions in Nijmegen. Will they grow larger, shrink in size, or even have left the region? These two developments form the so-called driving forces, because together they determine the future state of the world for Nijmegen municipality. Participants reached an agreement on robust actions that would work across scenarios.