Two interrelated facets of contemporary urban growth – population size and physical patterns of expansion – have received unequal attention by urban researchers. Urban expansion spurred by population growth may take different forms, with distinct consequences for quality of life, for the environment and for urban governance (Angel, 2006). What has emerged as a new challenge to the growth of urban areas in the 21st century is not only the pressure of numbers, but also the pressure that comes from the forms of consuming space in a globalized world. These patterns, and how they challenge the sustainable future of cities, are still insuffi ciently understood. Several forms occur simultaneously in different world regions, some of which are more sustainable than others. One of these forms is urban sprawl, a pattern of low-density settlement, widely regarded as undesirable from many perspectives.