The western city was conceived, from its origins, as a succession of full and empty spaces. The presence of those voids, unoccupied by buildings, permitted the construction of architectural landscapes, shaping the environmental character of cities and "expanding" their morphology and their memory. From the ancient city until those of today. these constructed voids have become significant spaces, beyond any specific use or function. In the times we live in, these landscapes, which reinforce the mechanisms of the cities' memories, are needed more than ever. To illustrate this process, we have selected architectural landscapes that are closely related to the memories of three cities: Paris, New York, and Rome.