East Asia's urbanization has taken place five to ten times faster than urbanization in Europe, North America, and elsewhere. The region includes Japan, South and North Korea, China, Hong Kong, Macao, and Mongolia. Although cultural and social differences in the region have led to distinct socio-cultural, political, and economic dynamics, spatial polarization, the emergence of mega-urban regions, world-cities, and regional, international and transborder development strategies are characteristic for East Asia's urbanization. Major challenges facing the region include sustainable economic growth, environmental sustainability, balanced urban development, spatial and administrative fragmentation, and the provision of affordable housing and services.