Canal

Canal, artificial waterway used for transportation, drainage, and irrigation. In 521 B.C. a precursor of the Suez Canal joined the Nile to the Red Sea. In China, the Ling Ch'u canal was completed during the 3rd century B.C. and the Grand Canal, joining the Paiho, Yellow, and Yangtze rivers, had sections in use by the 7th century A.D. The Romans built many canals to supply their cities with water and canalized a number of European rivers to create an empire-wide transportation system. In the 15th century the lock, a device for raising boats from one land level to another, was invented. Although one of the great engineering projects of the 19th century, the Suez Canal to the Red Sea, was built entirely without locks, the other great international waterway, the Panama Canal, would not have been possible without them. In North America the canal system included the Erie Canal (1825), linking the Hudson River to Lake Erie and providing an opening to the Middle West. The Welland Canal (1828), between Lake Erie and Lake Ontario, was the next step in an inland waterway transportation network, completed by the opening of the St. Lawrence Seaway (1959). The longest canalized system is the Volga-Baltic Canal (1965), which runs 1,850 mi (2,977 km), from Astrakhan up the Volga, via Kuybyshev, Gorkiy and Lake Ladoga, to St. Petersburg, Russia.