City is not only the political, economic, cultural, scientific, technological and educational center of a country or region, but also a powerful engine of economic growth
The three urban agglomerations of New York, Chicago and Los Angeles in the United States, Tokyo, Hanshin and Nagoya in Japan, and China's Yangtze River Delta, Pearl River Delta and Bohai Rim all contribute more than half of their economies
It can be said that any country or region should focus on the development of big cities.