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
Randolph Tower Randolph Tower Randolph Tower, formerly known as the Steuben Club Building, is a historic Gothic Revival skyscraper in Downtown Chicago. The building was constructed in 1929 and designed by architect Karl M. Vitzthum, who designed another Chicago landmark, the historic One North LaSalle Building. Randolph Tower was built for the Steuben Club of Chicago to promote German-American heritage. After the first World War, American citizens of German descent sought to found clubs to serve as a testimonial of their loyalty to the ideals of American citizenship. The first 25 floors were built for retail and offices and the club was