When vying for its Olympic bid, Beijing promised that it could stage a green games. So what makes an international event "green," and what's Beijing doing to prepare for its debut?
Although a certain amount of carbon dioxide (CO2) occurs naturally in the Earth's atmosphere, there are several human activities that increase levels of the greenhouse gas. See more »
Right now, landfills are all over the place. Yet, no one wants to live near one. So, what if we combined all of those landfills into one? How much space would it take up? See more »