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
Chicago Water Tower Pumping Station, it drew clean water from water cribs in Lake Michigan. The tower gained prominence after the Great Chicago Fire of 1871. While some incorrectly believe that the tower was the only building to survive the fire, a few other buildings in the burned district survived along with the tower. The tower was the only public building in the burned zone to survive, and is one of just a few of the surviving structures still standing. In the years since the fire, the tower has become a symbol of old Chicago and of the city's recovery from the fire.