As my cities' populations go up, so too do their unhealthiness and unhappiness. Cities that are big enough to work all the tiles in my big fat cross are going to be either too sick, or too unhappy, to work them properly. Now, with unhappiness, I've pretty much got that problem covered: I'll just get hereditary rule, and then spam cheap military units. Meanwhile, my old club-swinging warriors would simply be moved back to the city when they become obsolete, rather than paying the money to upgrade them. But, there's nothing I can spam - even expensive stuff - that can help with the unhealthiness. Sure, there's the National Park, but that doesn't come until much later in the game, and only works for one city. Any suggestions?