 The building, which is the third largest store in the world, was both declared a National Historic Landmark and listed on the National Register of Historic Places on June 2, 1978, and it was designated a Chicago Landmark on November 1, 2005.The building architecture is known for its multiple atria (several balconied atrium - "Great Hall") and for having been built in stages over the course of more than two decades.Its ornamentation includes a Louis Comfort Tiffany, (1848–1933), (later Tiffany & Co. studios of New York City) mosaic vaulted ceiling and a pair of well-known outdoor street-corner clocks at State and Washington, and later at State and Randolph Streets, which serve as symbols of the store since 1897.