I am reminded of the "Black Smoke" from various [cross-media] versions of "War Of The Worlds". Granted that an alien species may not fully want, need, or utiliz

I am reminded of the "Black Smoke" from various [cross-media] versions of "War Of The Worlds". Granted that an alien species may not fully want, need, or utilize native architecture but keeping such intact at least for initial reasons just after successful invasion has uses.