Seoul, located in the center of the western part of the Korean Peninsula, is a metropolitan city with excellent natural environment with 41.5km of Han River passing through the city. Seoul has been the Korean capital for 600 years and the center of politics, culture and economy of Korea, accounting for 23% of the Gross Domestic Product (GDP). Just merely 60 years ago, Seoul was in the ruins and ashes of war. It was one of the poorest cities, as the GNP per capita was only 82 dollars. However, Seoul has risen from the ruins of the war, and went through rapid urbanization in an extremely short period of time. Now the city became a world-class metropolitan city where over 10 million people call home. The city has now become a sustainable smart city with the ability to solve diverse urban problems such as housing, water and sewage, garbage, transportation and welfare.