Architecture of Chicago a new structural system of framed tubes in skyscraper design and construction. The first building to apply the tube-frame construction was the DeWitt-Chestnut Apartment Building which Khan designed and was completed in Chicago by 1966. This laid the foundations for the tube structures of many other later skyscrapers, including his own constructions of the John Hancock Center and Willis Tower (then named the Sears Tower) in Chicago and can be seen in the construction of the World Trade Center, Petronas Towers, Jin Mao Building, and most other supertall skyscrapers since the 1960s. Willis Tower would be the world's tallest building
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