Chicago is the third most populous city in the United States, with over 2.8 million living inside it, and is the largest city in the Midwest area. It has the nicknames "the Windy City", "Chi-town", and "the Second City".

Chicago was founded in 1833 near a portage between the Great Lakes and the Mississippi River watershed. The city became a major transportation and telecommunications hub in North America. Today, the city retains its status as a major hub, both for industry and infrastructure, with O'Hare International Airport being the second busiest airport in the world. In 2008, the city hosted 45.6 million domestic and overseas visitors.

In modern times, the city has taken on an additional dimension as a center for business and finance and is listed as one of the world's top ten Global Financial Centers. Chicago is a stronghold of the Democratic Party, and it has been home to many influential politicians such as the current President of the United States– Barack Obama.

Musically, the Chicago area has been the springboard of a variety of different bands from the seminal power pop group Material Issue to the pop/jazz rock band Chicago to blues superstar Howlin' Wolf– among very, very many others. It has also experienced a variety of musical scenes through history, perhaps most notably the development of electric blues (commonly known as 'Chicago blues').

Within Last.fm, this tag also often refers to the group Chicago or the musical "Chicago."