Chicago, officially the City of Chicago, is the most populous city in the U.S. state of Illinois, and the third-most-populous city in the United States. Chicago is an international hub for finance, culture, commerce, industry, education, technology, telecommunications, and transportation. Chicago was listed as an alpha global city by the Globalization and World Cities Research Network, and it ranked seventh in the entire world in the 2017 Global Cities Index. The Chicago area has one of the highest gross domestic products (GDP) in the world, generating $689 billion in 2018. In addition, the city has one of the world's most diversified and balanced economies, with no single industry employing more than 14% of the workforce. Chicago is home to several Fortune 500 companies, including Allstate, Boeing, Caterpillar, Exelon, Kraft Heinz, McDonald's, Mondelez International, Sears, United Airlines Holdings, US Foods, and Walgreens.
Major sections of the city include the central business district, called The Loop, and the North, South, and West Sides. In 2016, Chicago was ranked the sixth-most walkable large city in the United States. Many of the city's residential streets have a wide patch of grass and/or trees between the street and the sidewalk itself.
The city's waterfront location and nightlife has attracted residents and tourists alike. The city has many upscale dining establishments as well as many ethnic restaurant districts. Downtown is the center of Chicago's financial, cultural, governmental and commercial institutions and the site of Grant Park and many of the city's skyscrapers. Chicago lays claim to a large number of regional specialties that reflect the city's ethnic and working-class roots. Included among these are its nationally renowned deep-dish pizza; this style is said to have originated at Pizzeria Uno. One of the world's most decorated restaurants and a recipient of three Michelin stars, Alinea is located in Chicago. In 2003, Robb Report named Chicago the country's "most exceptional dining destination". In 2013, Chicago was chosen as one of the "Top Ten Cities in the United States" to visit for its restaurants, skyscrapers, museums, and waterfront, by the readers of Condé Nast Traveler.
Chicago Public Schools (CPS) is the governing body of the school district that contains over 600 public elementary and high schools citywide, including several selective-admission magnet schools. Lane Technical College Prep High School. is one of the oldest schools in Chicago and in 2012 was designated a National Blue Ribbon School by the U.S. Department of Education. Since the 1850s, Chicago has been a world center of higher education and research with several universities.