The Military in SimCity is a way to earn money, with the cost of ground. in SimCity 2000, when the city is big enough. the government will ask you if you allow a part of the city to be in military use, like an Airfield, but it is placed randomly in the area. in SimCity 4, you can simply unlock a military base, which is a Business Deal awarded after running low on your city's funds, but they also take a lot of place, like in other games. You cannot invade or attack other cities using Military, although some Disasters are similar to an attack, although not a ground invasion.In SimCity 3000 The Military Base is a reward after gaining a population of 100,000+.