Lefebvre argued that every society—and, therefore, every mode of production—produces a certain space, its own space. The city of the ancient world cannot be understood as a simple agglomeration of people and things in space—it had its own spatial practice, making its own space (which was suitable for itself—Lefebvre argues that the intellectual climate of the city in the ancient world was very much related to the social production of its spatiality). Then if every society produces its own space, any "social existence" aspiring to be or declaring itself to be real, but not producing its own space, would be a strange entity, a very peculiar abstraction incapable of escaping the ideological or even cultural spheres. Based on this argument, Lefebvre criticized Soviet urban planners on the basis that they failed to produce a socialist space, having just reproduced the modernist model of urban design (interventions on physical space, which were insufficient to grasp social space) and applied it onto that context: