Over the last few decades, the world has seen an increased gathering of its population in urban areas. This trend is far from new. Indeed, its persistence is marked by a remarkable increase in the absolute number of urban dwellers worldwide (UN-HABITAT, 2016). While in 1990 43% (2.3 ­billion) of the world’s population lived in urban areas, by 2015 this had grown to 54% (4 billion). And it continues to increase: aggregated predictions of the United Nations indicate that by 2050 the share of urban population is expected to reach 66% (UNDESA, 2014). Although this figure needs to be interpreted with caution due to inconsistencies in definitions and data availability, it emphasizes the urgent need to pay serious attention to this trend and to consider the positive and negative social, economic and environmental consequences carefully. Urbanization fosters economic growth and is generally associated with greater productivity and a better quality of life for all. Nevertheless, urbanization also often brings with it urban sprawl, environmental degradation, poor living conditions and severe problems of accessibility.