We live in a world which is becoming increasingly urban, where more and more people are moving to cities. Over 54 percent of people across the globe were living in urban areas in 2014 (UN DESA, 2014). The current urban population of 3.9 billion is expected to grow in the next few decades to some 6.4 billion by 2050 (ibid.). It is estimated that three million people around the world are moving to cities every week (UN-Habitat, 2009). Migration is driving much of the increase in urbanization, making cities much more diverse places in which to live.

Nearly one in five of the world’s foreign-born population resides in established global gateway cities (Çağlar, 2014). In many of these cities such as Sydney, London, and New York, migrants represent over a third of the population, and, in some cities such as Brussels and Dubai, migrants account for more than half of the population. Other cities have seen a remarkable growth in migration in recent years. For example, the number of foreign residents in Seoul has doubled in the last ten years. In Asia and Africa, rapidly growing small cities are expected to absorb almost all the future urban population growth of the world (UN DESA, 2014), and this mobility pattern to cities and urban areas is characterized by the temporality and circularity of the internal migration process (Hugo, 2014).