The outcome of the Great Chicago Fire led to the largest building boom in the history of the nation. Perhaps the most outstanding of these events was the relocation of many of the nation's most prominent architects from New England to the city for construction of the 1893 World Columbian Exposition.
In 1885, the first steel-framed high-rise building, the Home Insurance Building, rose in Chicago, ushering in the skyscraper era. Today, Chicago's skyline is among the world's tallest and most dense. The nation's two tallest buildings are both located in Chicago; Willis Tower (formerly Sears Tower), and Trump International Hotel and Tower. The Loop's historic buildings include the Chicago Board of Trade Building, the Fine Arts Building, 35 East Wacker, and the Chicago Building, 860-880 Lake Shore Drive Apartments by Mies van der Rohe, along with many others. The Merchandise Mart, once first on the list of largest buildings in the world, and still listed as 20th with its own ZIP code, stands near the junction of the North and South branches of the Chicago River. Presently, the four tallest buildings in the city are Willis Tower, Trump International Hotel and Tower, the Aon Center (previously the Standard Oil Building), and the John Hancock Center. Industrial districts, such as on the South Side, the areas along the Chicago Sanitary and Ship Canal, Chicago Southland, and Northwest Indiana are clustered.
Chicago gave its name to the Chicago School and was home to the Prairie School, movements in architecture. Multiple kinds and scales of houses, townhouses, condominiums, and apartment buildings can be found in Chicago. Large swaths of Chicago's residential areas away from the lake are characterized by bungalows built from the early 20th century through the end of World War II. Chicago is also a prominent center of the Polish Cathedral style of church architecture. One of Chicago's suburbs, Oak Park, was home to the architect Frank Lloyd Wright.
One of the city's most famous thoroughfares, Western Avenue, is one of the longest urban streets in the world. Other famous streets include Belmont Avenue, Pulaski Road, and Division Street. The City Beautiful movement inspired Chicago's Boulevards and Parkways.