This is done much the same way as crafting your own deck of cards in Magic the Gathering. For everyone who has ever wished they could design a winning civilization from scratch, Empire Earth finally provides this opportunity. Players choose from a large set of available attributes to customize their civilization in order to match a specific strategy. You can create a mighty civilization to help you conquer enemy nations, or you can create a defensive civilization in order to help you win through non-military means. For the empire builders among you, you can select from powerful economic bonuses, which will help your civilization's development over many epochs of history.
Customizable civilizations are important to single player campaigns as well.
In a campaign you start off with a civilization and attempt to take it through 4 - 8 epochs of world history. When you start a new campaign for the first time, the powers of your civilization are at their weakest. Throughout each scenario, you continue to be awarded civilization points for accomplishing your goals. You may spend these points right away in order to increase your civilization's economic, religious, diplomatic, or military skills. The civilization attributes you acquire belong to your civilization from that point forward.