Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega-cities over the last thirty years. A simple urban model illustrates that in closed...

Several Chinese cities have invested billions of dollars to construct new industrial parks. These place based investments solve the land assembly problem which allows many productive firms to co-locate close to each other. The resulting local economic growth creates new opportunities for real...