Sid Meirer (the creator of Civ) is to the simulation game what Henry Ford was to the transportation industry. That is to say he revolutionized it. Before Civ when one thought of a simulation game, games like SimCity came to mind. In SimCity you build a city, watch it grow, and take care of it for awhile... Then after a few hours the novelty wears off you go outside and get some much needed fresh air. You might play it a few other times when you're bored but, much like a model train set, the game doesn't really go anywhere.
Civilization took the idea of a simulation game and blew it up into the best strategy game (series of all time). Its been called the king of all "God games" (i.e. : simulation games). You start in the year 4000BC with a lone band of settlers. You found a city and let in grow for a few turns (this is where the similarities end). When this city becomes big enough it can spawn more settlers to farm the land, mine the hills, build roads and found new cities, expanding the empire. You can build military units as well, primative at first but more and more advanced as the years pass and you build upon your technology. Soon you encounter rival Civs, some friendly, some positively hostile. You can trade with them or war with them or simply try to peacefully coexsist. Ultimately your goal is to either conquer the world you are on (there are millions of possible maps the game can generate, making your world you play on new and different each time) or to skip town to Alpha Centuri by being the first to build an intersteller spacecraft. I could go on for hours about the intricacies of this game, but the beauty of it is, like life it is almost infinitely complecated, yet also like life, it can be appreciated right from the beginning without a complete and full awareness of all aspects.
When I first got the internet, back in '94 I wrote an advice file for Civilization and uploaded it onto AOL. Check it out below...
Links back