Civilization has the widest scope of any strategy game of its time. You are a leader of a nation. You begin in the Stone Age, and complete the game in the XXIth century (unless your civilization gets destroyed earlier). Your eventual goal is to become the dominant civilization in the world, either by wiping out everybody else, or being the first to get a space ship to Alpha Centauri. As the nation's leader, you have many responsibilities. You have to build cities, and then micromanage them, constructing various buildings. Most of people in your cities will be working on the neighboring lands to get food (without it, your city won't survive or grow), production (used to build military units and buildings) and trade (which can be exchanged for money, science (see below) or luxuries that make people happy. You decide how much trade you want to invest into each of these areas.) You have to make sure that your people are in a good mood; if they get too unhappy, the city will collapse into disorder, and won't produce anything until you fix the situation.