The 20th century is the century of the metropolitan revolution, in North America, the majority of people live in metropolitan areas, and the Northern metropolis is the centre of global economic and political power. Inequalities between and within metropolises are at the heart of the 'urban question', Despite attempts to stop metropolitan growth and warnings of the demise of big cities due to new technologies, the metropolis appears to be a relatively durable form of human settlement because of its economic and social complexity. Urban growth following the model of the North American metropolis, with its sharp central city-suburban imbalance, and automobile-centred, sprawled growth, is becoming more prevalent around the world. Thus, the socioeconomic inequalities and environmental problems associated with this model may well accompany global metropolitan growth in the 21st century. In the 21st century, planners will need to develop strategies for metropolitan growth and preservation that maximize the potential, inherent in this new settlement form, for energy efficiency and social equality.
