City construction, military development and the sustaining of military operations depend on 4 kinds of resources: oil, iron, steel and rare metals. Players will need to construct buildings to generate these resources in order to sustain growth and military operations as well as to build up their army. Resources can be obtained through these buildings or by plundering enemies. Gold is another special kind of resource, obtained by taxing one’s citizens. Gold is important for research, upkeep and various other functions vital to your city.