Imagine Earth is a simulation game. Your challenge is to raise a huge population on a planet and dealing with environmental problems. For your expanding cities you'll need to produce more and more resources. Production facilities increase the air and ground pollution. At least pollution induces global warming, that involves cataclysms as well as melting polar caps and a raising sealevel. You can do Ecology reseach and use renewable energy sources to prevent this. Please note that this is beta footage and the game is still in developement. Visit the project's website imagineearth.info to check out addional information.