ABSTRACT
This chapter provides an overview of current urbanization trends and the main challenges and opportunities cities are facing in the twenty-first century. Urbanization is considered as the increase in the proportion of population living in cities and settlements versus the population in rural areas. The evolution of cities from villages was supported by improvements in plant cultivation and livestock rearing in the Neolithic age, which allowed for higher-volume production and food storage and a departure from subsistence agriculture. This fundamental change led to an increase in surplus human labor that would be employed in nonagricultural work in cities. Rural populations tend to be drawn to cities for education and employment opportunities in the industrial and service sectors. Rapid urbanization is exerting pressure on fresh water resources, the living environment, and public health. With the urbanization trend, cities are gaining political attention over rural affairs and institutions, particularly in highly urbanized countries.
