How Long Did Cities Last in the Ancient World?

The National Science Foundation is funding a project looking at how long cities last in the ancient world. The idea behind it is that if we can figure out for the ancient world what factors contribute to longer lasting cities, maybe that applies today. It depends on the kinds of variables we were able to identify and whether they're comparable or not. And it also depends on people who pay attention to modern cities think that being at all irrelevant.