Oceanyka has approximately 400 million inhabitants, a large number of which inhabit its walled cities. To siege and take a city is no easy, or small, event. It requires an enormous deal of planning, ample logistics, and sufficient firepower. Sieges require encircling the target settlement using manoeuvre forces, after which it can be either cut of from food and ammunition supplies until it surrenders, demolished by bombardment, or assaulted by massed forces. The latter, in the modern day, requires excellent combined arms training; lone tanks will fall prey to any of the Cold War's hundreds of methods for tank-hunting such as RPGs or shaped charge mines, while lone infantry will pay in blood for every room cleared and every house secured.