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...

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...

Buenos Aires and Chicago grew during the nineteenth century for remarkably similar reasons. Both cities were conduits for moving meat and grain from fertile hinterlands to eastern markets. However, despite their initial similarities, Chicago was vastly more prosperous for most of the twentieth...