Notes

This animation of the most populous ten cities in the world reveals some fascinating broad sweeps of history

If you go back 4000 years, all the action is in the Middle East. Since then, virtually all the biggest cities in the world have been concentrated in a narrow swathe from the Mediterranean, through the Middle East and northern India, across China and into Japan. Only in the last couple of hundred years have northern European cities such as London and Paris, and American cities such as New York and Chicago, edged into the top ten.

It's also clear that most cities don't stay at the top for long. Especially these days. Rome, capital of the greatest empire of the ancient world, lasted in the list for rather less than 1000 years; London, however, capital of perhaps the most extensive empire the world has ever known, stayed on the list for less than 400 years. Lesser cities come and go in what seems the blink of an eye.

Lists of the most populous ten cities in the world are perhaps less meaningful now than they used to be. In ancient times, no city was viable if it was not surrounded by fertile farmland; in modern times, it's not clear where once city ends and the next begins. Moreover, population is no longer such a good proxy for power or wealth. Manila may be a city of 20 million people, but it's neither as wealthy as Paris nor as powerful as Washington.

Still, don't underestimate the significance of the New York's being the only city in the USA that appears in the latest list of top ten cities. North America and Europe remain richer than South America, Asia and Africa, but look at the map for 2008, and you have to wonder how much longer this will last.