The Chicago School of Architecture refers to a style of architecture that emerged in the late 19th and early 20th centuries in Chicago. It is characterized by the use of steel-frame construction, large plate glass windows, and functional design. This movement played a crucial role in the development of modern skyscrapers and urban architecture. Key figures of the Chicago School include architects like Louis Sullivan and Daniel Burnham, who emphasized the importance of form following function. Their innovative designs not only transformed the skyline of Chicago but also influenced architectural practices worldwide, laying the groundwork for modernist architecture.