Burj Khalifa with Smith's attempts to make the crown more slender. The building opened on 4 January 2010. The tower was designed by Skidmore, Owings and Merrill (SOM), which also designed the Willis Tower (formerly the Sears Tower) in Chicago and the One World Trade Center in New York City. Burj Khalifa uses the bundled tube design of the Willis Tower, invented by Fazlur Rahman Khan. Due to its tubular system, proportionally only half the amount of steel was used in the construction, compared to the Empire State Building. Khan's contributions to the design of tall buildings have had a profound impact
Chicago Water Tower Louisville Water Tower in Louisville, Kentucky. The Chicago Water Tower now serves as a Chicago Office of Tourism art gallery known as the City Gallery in the Historic Water Tower. It features the work of local photographers and artists, and filmmakers. The tower, built in 1869 by architect William W. Boyington from yellowing Lemont limestone, is 182 feet (55 m) tall. Inside was a 138-foot (42 m) high standpipe to hold water. In addition to being used for firefighting, the pressure in the pipe could be regulated to control water surges in the area. Together with the adjacent Chicago Avenue