It is certainly true that some of the world’s biggest cities today are dysfunctional nightmares, riddled with crime, squalor, and disease. But that, of course, has been true of most big cities throughout history. Rome had a million residents in the first century BCE; it also had street gangs that sometimes brought government to a halt and death rates so high that more than a thousand country folk had to migrate into Rome every month just to make up the numbers. Yet for all Rome’s foulness (brilliantly evoked in the 2006 HBO television series Rome), the organization needed to keep the city going was vastly beyond anything any earlier society could have managed—just as running Lagos (population 11 million) or Mumbai (population 19 million), let alone Tokyo (population 35 million), would have been far beyond the Roman Empire’s capabilities.
– Ian Morris, Why the West Rules – for Now: The Patterns of History and What They Reveal about the Future (2011)