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
Library Tower (Chicago) Library Tower (Chicago) Library Tower Chicago is located on 520 S. State Street, Chicago, Illinois, which is the block directly south of the main branch of the Chicago Public Library in the Loop community area. Currently (4/2009) the building has 184 Units. 52 units have been sold and closed. Another 36 are under contract. Apparently, the building was mostly sold unit the economy forced investors to pull out of the building, leaving it largely unsold. Units have been on sale since 2005, with closing first occurring in 2008. There has been substantial price drops from being on the market (1