Grand Canal (China)

The Grand Canal or Dayunhe or Jing–Hang Grand Canal () is the longest and oldest canal and artificial river in the world. 
It starts in Beijing; passes through Tianjin, Hebei, Shandong, Jiangsu and Zhejiang; and ends in Hangzhou.
It connects China's two longest rivers: the Yellow River and the Yangzi. 
The oldest parts of the canal were built during the 5th century BC. 
The Sui dynasty (581–618 AD) added some other parts. Between 1271–1633, the Yuan dynasty (through Guo Shoujing and others) and the Ming dynasty improved it and built parts to direct water to Beijing. 
The total length is . Its greatest height is 42 m (138 ft) near the Shandong mountains.
Song Dynasty (960–1279) engineer Qiao Weiyue invented the pound lock in the 10th century. This allowed ships to travel higher and lower through the canal. 
The canal amazed many people throughout history including Japanese monk Ennin (794–864), Persian historian Rashid al-Din (1247–1318), Korean official Choe Bu (1454–1504), and Italian missionary Matteo Ricci (1552–1610).
Historically, flooding of the Yellow River threatened to break the canal. During wartime the canal was even used as a weapon: the dikes of the Yellow River were sometimes broken to flood the enemy troops. But this caused disasters and hurt the economy. 
The Canal has greatly improved China's economy and increased trade between the north and south. It is still used heavily to this day.
It is a UNESCO World Heritage Site.