Countless policy makers and researchers have flocked to observe the education systems of Hong Kong, Shanghai and Singapore, which are among the top five performers in the PISA (Programme for International Student Assessment) 2009 reading assessment. Many visitors have been particularly impressed by the fact that these education systems succeed in embracing the social heterogeneity in their student populations that is intrinsic to large urban environments--something that many other education systems struggle to achieve. But large cities do not just pose social challenges to educators; they also offer important advantages for schools, such as a richer cultural environment, a more attractive workplace for teachers, more school choice, and better job prospects that can help to motivate students. New analyses from PISA highlight these advantages, showing that, in several countries, students from urban areas (defined here as cities with over a million inhabitants) do as well as students in PISA's top performing city-states, even if the different push and pull factors of urban environments play out very differently across countries. This paper reports that: (1) Large cities are generally educational assets: in most countries, performance improves dramatically when only the scores of students in urban areas are considered, although this is not the case in some countries, such as Belgium, Slovenia, the United Kingdom and the United States; and (2) When comparing the performance of students in large cities, students in Portugal and Israel perform as well as those in Singapore, and students in Poland perform as well as those in Hong Kong.