CHENGDU, CHINA--The hydrolic works at Dujiangyan, a little more than an hour northwest of Chengdu are pretty breathtaking even by contemporary standards. The complex divides the Minjiang River, controlling flood levels as well as providing stable irrigation to the rich countryside leading to Chengdu and eventually to the Yangtze River. Li Bing, the governor of the Shu Prefecture of the Qin State, realized that perpetual flooding was strangling the economic life of his people. (The plain before the works were built was an octopus of rivers and creeks, making most of the farms vulnerable.)
Over the course of 17 years, Li Bing engaged thousands of workers, built a dike to divide the river, created two spillways that would regulate the water level using winch technolgoy, and broke through a mountain to create pass for the "outer" river. All this was accomplished in 250 BC. The works still operate, and are a dramatic testament to the scientific achievement of ancient Chinese culture.
Unfortunately, the technology and scientific know-how, while inscribed on the temples surrounding the works, never made it out of China. Surely, a freely functioning global trading system would have ensured that would have happened. The idea that something so innovative would today sit passively without notice by the rest of the world is virtually unheard of in a global economy knitted together by trade and competition.
But, the scientific advances of China didn't have much of a chance prior to the industrial revolution. Chinese emporers were so convinced of their culture's superiority, they closed the nation to the world, severing burgeoning trading routes and closing off the Silk Road. The result? China lost its cultural, economic, and scientific pre-eminence. In 1500, China claimed 6 of the world's top 20 cities, the most of any major region, according to Coming Full Circle: An Economic History of the Pacific Rim. India claimed title to 4 of the world's largest cities and Southeast Asia was home to another. In other word's, Asia ruled.
By the 1925, China could claim only one of the world's largest cities and India could claim only one. The U.S. had 5.
Of course, we all know that China began opening itseful up to trade and market-based development in 1979-1980. Since then, its economy has flourished. Now, according to the United Nations, China once again has three of the world's top twenty: Shanghai, Beijing, and Shenzen, with several others growing rapidlly.