S. R. Crown Hall, designed by the German-American Modernist architect Ludwig Mies van der Rohe, is the home of the College of Architecture at the Illinois Institute of Technology in Chicago, Illinois. S.R. Crown Hall was named a Chicago Landmark in 1997, a National Historic Landmark in 2001, and the remainder of the IIT Main Campus was entered into the National Register of Historic Places in 2005. The enclosed space is column free with four six ft. steel plate girders welded to eight H-columns. These girders suspend the roof in a single plane to form a primary structure. While the lower level consists of compartmentalized rooms, the upper level occupies almost 50% of the total area of the building, but only includes one large, open classroom.