canal
Canal is the scale of artificial excavation is relatively large, can make the flow of water through the channel. Canals are usually connected to lakes, rivers and oceans, or across the peninsula, the isthmus and made. China's Xu River is the earliest recorded canal, is also the world's first canal excavation, excavation in the year 506 BC. China's Beijing-Hangzhou Grand Canal is the longest canal in history, about 1,700 km, but today only a small number of sections for shipping. The longest canal in the world is the Karakum Canal in southern Turkmenistan, about 1375 kilometers long, and most of the river can be sailed. ...