I do want to save the world. I want to build 'green cities'. If we don't change the way we live, and the cities we live in, we'll destroy this planet in the next fifty or a hundred years. Green cities are the answer to this problem. If we build houses from environmentally friendly materials, if we use natural power from the sun and the wind, if we recycle our garbage, if we plant more trees and open more parks, the world will be cleaner and greener.