In China, Chengdu is always praised as the Tian Fu Zhi Guo, which means 'Nature's Storehouse'. Over 2,200 years ago, the city was threatened by the frequent floods caused by flooding of the Minjiang River (a tributary of the Yangtze River). Li Bing, a local official of Sichuan Province at that time, together with his son, decided to construct an irrigation system on the Minjiang River to prevent flooding. After a lengthy study and a lot of hard work by the local people, the great Dujiangyan Irrigation Project was completed. Since then, the Chengdu Plain has been free of flooding and the people have been living peacefully and affluently. Now, the project is honored as the 'Treasure of Sichuan', which still plays a crucial role in draining off floodwater, irrigating farms and providing water resources for more than 50 cities in the province. Dujiangyan is the oldest and only surviving no-dam irrigation system in the world, and a wonder in the development of Chinese science.