Chicago is the largest city by population in the state of Illinois and the American Midwest, United States. It is a dominant center of finance, industry and culture in the region. The city, for much of its history, has been known informally as America's "Second City." It is currently ranked as the third-most populous city in the United States after New York and Los Angeles, with a population of nearly 3 million people. The Chicago metropolitan area (commonly referred to as Chicagoland) has a population of over 9.7 million people in Illinois, Wisconsin and Indiana, making it also the third largest metropolitan area in the U.S. Adjacent to Lake Michigan, it is among the world's twenty-five largest urban areas by population, and rated an alpha world city by the World Cities Study Group at Loughborough University. Often called The Windy City and The City of Broad Shoulders, Chicago was incorporated as a city in 1837 after initially being founded in 1833 near a portage between the Great Lakes and the Mississippi River watershed. The city soon became a major transportation hub in North America and quickly became the transportation, financial and industrial center of the Midwest. Today the city's attractions bring 44.2 million visitors annually. Chicago was once the capital of the railroad industry and until the 1960s the world's largest meatpacking facilities were at the Union Stock Yards; currently the city is home to the nation's second busiest airport, O'Hare International. Chicago became notorious worldwide for its violent gangsters in the 1920s, most notably Al Capone, and for the political corruption in one of the longest lasting political machines in the nation. The city has long been a stronghold of the Democratic Party and has been home to numerous influential politicians including the current presidential nominee, Barack Obama.