The challenge for the cities of tomorrow lies in breaking the segregation and turning the diversity into a creative force for innovation, growth and well-being (European Union 2011). Socio-economic, ethnic and cultural diversity may have positive effects on social cohesion, economic performance and social mobility. Much depends on the perspective on diversity, and whether we regard the city as a cluster of problems or as a place of freedom and creativity. Therefore the urban population, in particular migrants, must not be looked on as a burden and source of deficit but as an opportunity. In fact there is a positive correlation between the proportion of foreigners and urban economic wealth which may be explained both by immigrants’ attraction to economically wealthy cities, and by the economic opportunities created by diversity.