Chicago Many other architects have left their impression on the Chicago skyline such as Daniel Burnham, Louis Sullivan, Charles B. Atwood, John Root, and Helmut Jahn. The Merchandise Mart, once first on the list of largest buildings in the world, currently listed as 44th-largest (), had its own zip code until 2008, and 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 (formerly the Sears Tower, also a building with its own zip code), Trump International Hotel and Tower, the Aon Center (previously the Standard
The Gogo Building district along the Chicago River. There are two large red brick buildings along the Chicago River just south of where the river splits, formerly known as the Butler Brothers Warehouse buildings. They were both designed for the Butler Brothers Company, a mail order company, similar to Montgomery Ward's and Sears & Roebuck at the time. The northern structure was designed by Daniel Burnham, a famous Chicago architect, with its completion date being 1913, a year after Burnham’s death. This building only stood for 7 years before being completely demolished and rebuilt exactly as it stood before by the Chicago Union