there will be an option to turn on war in your settings when making a singleplayer world (but also an option to turn off ai aggression) or if you're the owner of a multiplayer world, and you can turn it on or off at any time to create more interesting scenarios.. in the case of single player if you have already built several cities with their own militaries they can go to war with eachother by themselves or if you turned off ai aggression then you're the one who goes to war, when this happens both cities will fire missiles at eachother and send their armies into eachother but the ai would have a scale on how aggressive it will be with its weapons depending on how much they're losing, like if they've almost lost the war they can launch a missile but you can also launch a missile to destroy that missile before it lands in your city. When the war is over and one side has won there will peace terms which will either be (1. absorb enemy city, 2. vassalize enemy city [you collect 50% of money and it is technically apart of your domain but the person who owned it will still own it], 3. seize electricity [take 50% of enemy's electricty for next 10 years] 4. seize water [take 50% of enemy's water for next 10 years], and an extra term which might not be realistic to add, taking parts of your enemy's city like taking the small plot sizes out of your medium sized enemy's city and absorbing it into yours.) After the war is over the city's population will begin rioting for independence some time after the war if you absorbed it.. if over 60% of the city riots then they will become independent, these riots will only happen if you do not make repairs on most of the damages you did and keep happiness above 70% for 5 years in a row, if you do then the riots will subside but if you begin losing another war they may come back, and also the person who had their city vassalized can declare a war of independence if they want to.. i feel like this could make more interesting multiplayer servers and make diplomacy and militaries interesting
