Canal with a basic lock arrangement. Boats traveling upstream pass from the lower to the upper pool elipsis
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End portion of the alimentary canal, distinguished from the rectum by the transition from an internal mucous membrane layer to one of skinlike tissue and by its narrower diameter. Waste products move from the rectum to the anal canal. The human anal canal is 1–1.5 in. (2.5–4 cm) long and has three parts: upper, with longitudinal folds (rectal columns); lower, with involuntary and voluntary constrictive muscles (sphincters) to control discharge of feces; and the anal opening itself. Enlargements of the ends of rectal and anal veins are called hemorrhoids.
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Canal, southeastern Ontario, Canada. Linking Lake Huron with Lake Ontario, the canal extends from the southeastern shore of Georgian Bay up the Severn River to Lake Simcoe, connects several lakes of the Kawartha Lake region to Rice Lake, and passes down the Trent River to the Bay of Quinte and Lake Ontario. Its 242-mi (389-km) main course consists of 33 mi (53 km) of man-made channels and 42 locks. Construction began in 1833. The waterway once served a busy lumber trade; it is now a popular tourist attraction.
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Ship canal, Isthmus of Suez, Egypt. Connecting the Red Sea with the eastern Mediterranean Sea, it extends 101 mi (163 km) from Port Said to the Gulf of Suez and allows ships to sail directly between the Mediterranean and the Indian Ocean. Built by the French-owned Suez Canal Co., it was completed in 1869 after a decade of construction. Its ownership remained largely in French and British hands until Egypt nationalized it in 1956, setting off an international crisis (see Suez Crisis). It has a minimum width of 179 ft (55 m) and a depth of about 40 ft (12 m) at low tide. Though protected by international treaty, the canal has been closed twice. The first closing was during the Suez Crisis. The canal was closed again by the Six-Day War (1967) and remained inoperative until 1975. It is one of the world's most heavily used shipping lanes.
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Lock-type canal, Panama. Extending across the Isthmus of Panama, it connects the Atlantic and Pacific oceans. It is about 50 mi (82 km) long from deepwater to deepwater, with an average depth of 43 ft (13 m). The width varies between 500 to 1,000 ft (150 to 300 m). In 1881 a French company began constructing the canal, but the enterprise collapsed in 1889. Under a 1903 treaty Panama granted the U.S. the Panama Canal Zone and the rights to build and operate a canal. Work began in 1904; facing enormous obstacles, George Washington Goethals directed the construction from 1907, and the canal opened on Aug. 15, 1914. The canal enabled ships traveling between the two oceans to avoid the lengthy circumnavigation of South America and was a boon to world commerce. After disputes over sovereignty, a 1977 treaty provided for Panama to take control of the canal by 2000; it did so in 1999. Except for small craft, no vessel can pass through the canal under its own power. Ships are towed by electric locomotives, and it generally takes 15–20 hours to complete the passage (including waiting time). Sets of double locks enable ships to pass in opposite directions simultaneously.
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Deep fjord, southeastern Alaska, U.S. An important gateway to the Klondike region, it is 80 mi (129 km) long and 6 mi (10 km) wide. The northernmost fjord to penetrate the Coast Mountains, it was named in 1794 by Capt. George Vancouver for his birthplace, King's Lynn, Eng.
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Neighbourhood in Niagara Falls, N.Y., the site of the worst environmental disaster involving chemical wastes in U.S. history. Originally the site of an abandoned canal, it became a dumping ground for nearly 22,000 tons of chemical waste in the 1940s and '50s. The canal was later filled in, and housing was built on it. The leakage of toxic chemicals into these homes was detected in 1978, and residents were discovered to have a high incidence of chromosome damage. After their evacuation, 1,300 former residents obtained a $20 million settlement from the dumping company and the city. In the early 1990s New York state ended its cleanup and declared parts of the area safe for residence.
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Series of waterways in northern China that link Hangzhou with Beijing. Some 1,085 mi (1,747 km) in length, it is the world's longest man-made waterway. It was build to enable successive Chinese regimes to transport surplus grain from the agriculturally rich Yangtze (Chang) and Huai river valleys to feed the capital cities and large standing armies in the north. The oldest portion, in the south, may date from the 4th century BC. Expanded over the centuries, it continues to be used today for shipping and irrigation.
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Historic waterway, northern U.S. It stretches from Buffalo, N.Y., on Lake Erie to Albany, N.Y., on the Hudson River. Commissioned by Gov. DeWitt Clinton of New York, it opened in 1825. It connected the Great Lakes with New York City and contributed greatly to the settlement of the Midwest, allowing for the transport of people and supplies. Enlarged several times, the canal is 363 mi (584 km) long, 150 ft (46 m) wide, and 12 ft (3.6 m) deep. Now used mainly for pleasure boating, it is part of the New York State Canal System.
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Park, eastern U.S. It consists of the former Chesapeake and Ohio Canal, a waterway running along the Potomac River between Washington, D.C., and Cumberland, Md. The canal, which extends 185 mi (297 km), was built beginning in the 1820s. Competition from the railroads later caused its economic decline. The canal was purchased in 1938 by the U.S. government; it was restored and established as a historical park in 1971.
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Strip of territory, a historic administrative entity in Panama over which the U.S. formerly exercised jurisdictional rights (1903–79). The zone came into being in 1904 when Panama granted the U.S., in return for annual payments, sole right to operate and control the Panama Canal, including a strip of land 10 mi (16 km) wide along the canal extending from the Atlantic to the Pacific Ocean and bisecting the Isthmus of Panama. The zone was abolished by treaty in 1979, and civil control of the territory was returned to Panama. By the same treaty a commission under joint U.S.-Panamanian ownership was established to operate the canal until the year 2000, when Panama assumed full control.
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The Inland Waterway or Inland Water Route is a series of streams and lakes in the U.S. state of Michigan. With only a short portage, it forms a navigable route for small craft connecting Lake Huron and Lake Michigan across the Northern Michigan region.