The past century has seen the rise of an urban and suburban landscape that is profoundly different from anything created before. From the office parks, malls, freeways, residential tracts, and abandoned inner cities of many affluent countries to enormous megacities in developing countries, human communities have taken on dramatically new forms and characteristics, with radically new lifestyles and economies. Cities that once occupied a few square miles now cover thousands; populations that once walked most places are now dependent on motor vehicles. People are surrounded by vastly larger quantities of material goods, but often feel the lack of social connection, meaning, or ability to control their world.