Urbanism, an overview

Past and current experiences can be studied in order to understand the main phenomena driving urbanization and thus to better anticipate the future challenges for cities. We distinguish between the main historical time periods of cities. Then, we discuss some regularities related to the internal structure and the spatial distribution of cities. We present some main demographic forecasts up until the end of the century, and highlight the major challenges for cities. We conclude with the need for Policymakers to take into account externalities (among regions and cities), and to define policy targets at the inter-city level.