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
Joshua Sears Building works on what is now Peter Kirk Park. The building originally intended to house a bank at the corner. Sears outfitted the entire interior and even hired a partial staff but with the arrival of the Panic of 1893, the doors, like the steel mill, never opened. In the years after the bust, the building, like many others in the area remained mostly vacant, though it, along with a large portion of the original townsite remained in the ownership of the Sears estate. The corner space was eventually occupied by a printing company and later a grocery store. An electric