In times of increasing population densities in metropolitan areas, urban development issues have moved back forcefully onto the agendas of researchers and policy-makers. On the one hand, cities attract the most productive economic agents by providing a competitive environment where knowledge and technology diffuses quickly. On the other hand, cities face challenges in terms of congestion, high costs of living and social disruption. To discuss the push and pull factors of modern metropolises from a theoretical and from a policy point of view, experts came together on 12-13 October 2009 at FEEM during the first Conference in Urban and Regional Economics (CURE) and the subsequent roundtable, which was jointly organised by FEEM and the Camera di Commercio of Milano. This article summarises some of the ideas that emerged from the two-day meeting.