http://www.newyorkfed.org/research/epr/02v08n2/0211harr.pdfInternational audienceThe September 11 attacks in New York and Washington have forced Americans to confront the fact that to live or work in a large city is to be at greater risk of large-scale terrorism. What do these risks, and the public perception of them, imply for cities in general and the future of New York City in particular? In this article, the authors begin their exploration of this issue by examining why cities exist in the first place. To conduct their analysis, they simulate two key theoretical models of economic geography, using data that approximate the characteristics of a major U.S. city as well as estimates of the costs of the September 11 attacks. The authors con...