Current world trends indicate that increasingly the health of our Earth and its inhabitants are inextricably tied to the future of our urban centers. According to the United Nations, the year 2005 marked the first time in our planet’s history that over half of the entire human population lived in cities. In western countries, this percentage is even higher, with 80 percent of the population living in urban areas. In addition, these trends of urbanization are on the rise, particularly in developing countries. Between 1990 and 1995, 263 million people were added to cities in developing countries. This is equivalent to the formation of a new Los Angeles or Shanghai every three months. More

