The article considers the importance of preserving the architectural environment's national identity in terms of its defense’s effectiveness in modern military operations. A brief overview of the traditional urban characteristics of Ukrainian cities, which in the past ensured their effective defense, was made: the way the buildings are located in the landscape, the planning structure, the height of the buildings, and the density of their location on the territory. The local landscape was actively involved in the architectural organization of the environment, which ultimately determined the unique plan structure for each city and the individual routing of the street network. If necessary, elements of the local landscape were supplemented with artificial systems and used for defense. A significant perimeter of cities with a predominance of traditional manor buildings created difficulties for the organization of the enemy encirclement. Internal fortifications around individual structural elements of the city contributed to long-term defense. To protect large areas, a system of tree-earth ramparts was artificially created. In the past, these measures helped to defend Ukrainian cities effectively. The events of the Russian-Ukrainian war, among other things, revealed that modern weapons, with all their capabilities, could not always overcome landscape obstacles, in particular, ancient defensive walls and swampy areas north of Kyiv; cities that preserved the traditional character of the architectural environment defended more effectively; flat regions of cities, compared to those located on rugged terrain, found themselves in a more threatening situation, etc. All these facts will obviously be subject to detailed analysis in the future. Still, it is already possible to conclude that the preservation of traditional identity in the conditions of a modern architectural environment is essential not only for the self-identification of residents or for the formation of the attractiveness of urban space but also for practical reasons of organizing the effective defense. After all, in the process of long-term formation of the architectural space’s traditional features, the defensive potential of the local landscape many times passed a practical test of its effectiveness by military operations in different historical periods.