The political unity under the
Sui dynasty (589-618) made it possible to build the Grand Imperial Canal (607-10) which is the world's longest man-made waterway. Building techniques were primitive, and the peasants, who did most of the work, endured much suffering. About half of the six million men recruited to build the Canal died at their work. This contributed to the downfall of the shortlived Sui dynasty.

The Canal stretches over 1,000 miles in length and links the Yellow and Yang-tze river systems. This 'artificial Nile' accomplished for China what the real Nile had done for Egypt thousands of years ago.

It integrated the north and the south and formed the basis for a unfied Chinese national economy. It also restored the authority of the imperial officials who were needed for the administration and maintenance of the Canal. Hence the foundations was laid for the brilliant epoch of the Tang dynasty (618-907) as China emerged as the most powerful state in the world.