John Hancock Center

Chicago is the largest city in the U.S. state of Illinois and the third most populous city in the United States, with nearly 2.7 million residents. Its metropolitan area, sometimes called "Chicagoland," is the third largest in the United States, with an estimated 9.8 million people in the states of Illinois, Wisconsin and Indiana. Chicago is the county seat of Cook County, the second most populous county in the United States. Chicago... was incorporated as a town in 1833, near a portage between the Great Lakes and the Mississippi River watershed. Today, the city retains its status as a major hub for industry, telecommunications and infrastructure, with O'Hare International Airport being the second busiest airport in the world in terms of traffic movements. In 2008, the city hosted 45.6 million domestic and overseas visitors. Among metropolitan areas, the Chicago area has the 4th largest Gross Domestic Product in the world. Chicago is an important worldwide center of commerce. The city has one of largest financial centers in the United States. The world cities study group at Loughborough University recognized Chicago among its leading group of cities.
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