The buildings and architecture of Chicago have influenced and reflected the history of American architecture. The built environment of Chicago is reflective of the city's history and multicultural heritage, featuring prominent buildings in a variety of styles by many important architects. Since most structures within the downtown area were destroyed by the Great Chicago Fire in 1871 (the most famous exception being the Water Tower) Chicago buildings are noted for their originality rather than their antiquity.
Chicago is world-famous for its plethora of unique architectural styles, from Chicago Bungalows and Two-Flats to the grand Graystones along Logan Boulevard and Lawndale, from the skyscrapers of the Loop as well as a wealth of sacred architecture such as the city's ornate "Polish Cathedrals".
Beginning in the early 1880s, architectural pioneers of the Chicago School explored steel-frame construction and, in the 1890s, the use of large areas of plate glass. These were among the first modern skyscrapers. William LeBaron Jenney's Home Insurance Building was completed in 1885 and is considered to be the first to use steel in its structural frame instead of cast iron, but this building was still clad in heavy brick and stone. However, the Montauk Building, designed by John Wellborn Root Sr. and Daniel Burnham, was built in 1882–1883 using structural steel. Daniel Burnham and his partners, John Welborn Root and Charles Atwood, designed technically advanced steel frames with glass and terra cotta skins in the mid-1890s, in particular the Reliance Building; these were made possible by professional engineers, in particular E. C. Shankland, and modern contractors, in particular George A. Fuller.