The Yangzi River, the world's third longest river at 6,280 kilometres (3,900 miles), is the symbolic lifeline of China. Flowing from Tibet to Shanghai, and cutting through the dramatic mountains of the Yangzi river basin, the Chinese people have long seen the river's power and beauty as representing the nation itself. Historically, the Yangzi served as a divider between northern and southern China, a natural barrier against invaders and a waterway for transport and commerce. The river basin is the country's heartland, home to 500 million people - a tenth of the world's population.