For several thousand years, the world has been experiencing increased urbanization. In 2008, the UN Population Fund announced that the world now has more urban than rural inhabitants(1), and this trend is far from slowing down. It is projected that between 2007 and 2050, the population of the world will increase by 2.5 billion, at which point two thirds of the developing world will reside in urban areas.(2) Approximately 75% of this rapid expansion is expected to be found in smaller cities (500,000 to 1.6 million people), which currently house more than 50% of the world’s urban population.(3) Cities offer many health benefits, including large markets with a reliable food supply, economies of scale, stable public services, and a collection of educated individuals that contribute to enterprise, education, and innovation