During the1990s, a certain number of notions were formulated in an attempt to conceptualize the territorial forms of the city emerging in Europe at the time, that is to say, the continuous constellation of urban layers that was spreading over hundreds of kilometers and reinterrogating the notion of the city and dwelling. The Città diffusa, the city-territory, the emerging city, the generic city, Metapolis, the hyperville, the Zwischenstadt: while the Pompidou Center put on a major exhibition about La ville, art et architecture, (The City, Art and Architecture), the journal Le Visiteur contributed to this debate by publishing texts on the contemporary city by Melvin Webber, André Corboz, Bernardo Secchi and Rem Koolhaas. Starting from the principle that the context was not the expansion of cities but a “deepening” of territories, there was a profusion of new terms for the urban phenomenon that sought to capture what the old words could no longer grasp. The birth and dissemination of the vocabulary of the urban must be related to the appearance in the 2000s of a certain number of approaches to large-scale projects that were diverse in nature, and that in turn reinterrogated the contours of the city-territory in which they were inscribed, while operationalizing reflection. From observation to action: after the high points where interests converged; divergences came to the fore and shattered the basis of representation, revealing ambiguities, eliciting controversies, while more discreet trajectories were taking shape. What do these discrepancies and these frictions that are shaping the urban tell us? Formulating the project: along what paths can collective action direct itself in order to define an ecology of the city-territory?