Retrofitting our cities

A friend sent this to me. Ecocitybuilders has done a before and after rendering of what a city might look like if it was retrofitted for pedestrians and rebuilt with recycled building material. While this might seem a bit out of the future (remember blade runner), as an urban planner I really think that a major challenge in the next 50-100 years is how are we going to retrofit cities to be more livable, economic, and pedestrian friendly. The Ecocitybuilders might not be all that far off from the mark. Some of our urban centers are this green (Portland and San Francisco come to mind) that have integrated nature into the city.