Chicago, on Lake Michigan in Illinois, is among the largest cities in the U.S. Famed for its bold architecture, it has a skyline punctuated by skyscrapers such as the iconic John Hancock Center, 1,451-ft. Willis Tower (formerly the Sears Tower) and the neo-Gothic Tribune Tower. The city is also renowned for its museums, including the Art Institute of Chicago with its noted Impressionist and Post-Impressionist works. hicago was incorporated as a city in 1837 near a portage between the Great Lakes and the Mississippi River watershed and grew rapidly in the mid-nineteenth century. After the Great Chicago Fire of 1871, which destroyed several square miles and left more than 100,000 homeless, the city made a concerted effort to rebuild. The construction boom accelerated population growth throughout the following decades, and by 1900 Chicago was one of the five largest cities in the world