The global world is mobile, crossed by flows and organized in networks. But it is also a world of material and immaterial borders, that disappear, multiply, displace and relocate elsewhere. Cities are a crucial space to analyze the restructuring of the political, economic, social and cultural order. In the cities the global world takes locally shape. Despite the multiple configurations and the structural differences of urbanization processes in the world, cities continue to be very interesting laboratories, potentially open to political and social innovation.
Keywords: Cities, global urbanization, complexity, mobility, borders, citizenships.