There is a unmistakable logic to this system of defense. While walls and towers are classic features of medieval defenses, they were made obsolete by increasingly stronger cannons and artillery. In Shura City, walls are not meant to keep people out so much as they are designed to hide people from cameras. It's design for the warfare of our time, in which the United States favors sending robots, over people, to hunt down small groups or individuals. Interestingly, Shura City has no real defenses designed to deter drones (except, maybe, for those detonating machines). It simply tries to build a community of obscurity, where drone operators cannot isolate a target.