Grand Canal

 The Grand Canal is an artificial waterway in China extending from Hangzhou north 1,100 miles to just outside of Beijing.  It is nominally the longest artificial waterway in the world.  Unfortunately, though, several sections have fallen into disrepair.  Thus, the Grand Canal is not currently continuous.  The oldest portion, dating to approximately the sixth century BC, links the Yellow River near Kaifeng with the Si and Bian Rivers.  Another portion, built in the fifth century BC, connects the Yangtze River to the Huai River.  It was built for and used by the Emperor of the State of Wu for the transport of troops and supplies during his campaign against the northern State of Qi.  Over the next thousand years, the waterway was extended north.  Chinese engineers invented the double-gate lock system so as to allow the canal to cross highland areas.  Dikes and dams were also constructed to regulate water flow through the Grand Canal, a process emulated by the Panama Canal today, albeit on a much larger scale.  Even when the Grand Canal reached Beijing in 609 AD, it still was not continuous.  There were several places where cargoes had to be unloaded from one barge, hauled overland, and loaded onto a waiting barge.  The waterway was finally completed in 1280.  Continual effort was required to maintain its navigability.  The Grand Canal served as an economic engine for eastern China.  Many towns and cities along its route prospered.  Huge amounts of grain were moved north and many finished goods were moved south through the canal.  Shipyards built specialized barges for use on the Grand Canal.  A roadway was built alongside the canal for use by government couriers.  Massive floods on the Yellow River in 1855 heavily damaged the Grand Canal in that vicinity.  The canal has never fully recovered from that disaster.  Efforts have been made to rehabilitate damaged and deteriorated portions, but the work has yet to be completed.  Marco Polo mentions the Grand Canal in the recounting of his 13th century trip to China.  In the 16th century, the Roman Catholic missionary Matteo Ricci traveled the Grand Canal from Nanjing to Beijing.