The opening of the economy to external markets has brought about the re assessment of the significance of large spatial agglo--merations and the accentuation of polarization at national scale. The dual movement of centralization and de-concentration proces--ses, inwards and outwards, contributes to urban sprawl beyond the limits of metropolitan areas, as has been demonstrated in Shang--hai, Jakarta, Delta Metropolis, Mexico City, Sao Paolo and Santia--go. lts consequences for urban structure and urban morphology are immense and complex, and it has fostered social fragmentati--on of space, changing location opportunities, land uses and centra--lities. The importance of transport and communication is accentua--ted, large intra and inter urban connectivity are generated together with the generation of articulated networks, corridors, nodes with impact in land values. New lifestyles, new urban environments and new form of governance emerge and need to be theoretically and empirically underpinned.