(en) Morphological approaches to the study of cities and territories have profoundly altered theories of urbanism. Highlighting the structural effects inherent to urban formation processes has helped to relativize the impact of conjunctural determinations. However, these approaches are often biased by formalist or conservative aims. In reaction, architects like Aldo Rossi and Rem Koolhaas praise architectural acts that are able to deflect urban genesis from expected trajectories. However, these two approaches are complementary. Morphological analyses depict the city as a material structure where every architectural intervention that inflects its development can be seen as an event. In complement, the importance of these inflections is enhanced through the narrative of their production. In other words, both morphological and narrative descriptions reveal that urban processes are above all opportunities for events to happen. As such, the persistence of urban processes matters more than their origin or their goal. The aim of this research is to understand how these events happen, and how the vitality of the process maintains itself, by analyzing the motives of a number of protagonists. The political issues that underlie recurrent modifications of urban morphology are highlighted through the study of the history of Brussels. Paradoxically, partisan commitment requires architectural propositions that are generous enough to have a significant impact. However, the crucial point is to understand the supplementary effect induced through the superimposition of successive interventions. The coexistence of several fragmentary interpretations of urban structures provides a propitious condition for new events. The concept of “indivision” defines this particular quality.