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
Chase Tower (Chicago) Chase Tower (Chicago) Chase Tower, located in the Chicago Loop area of Chicago, in the U.S. state of Illinois at 10 South Dearborn Street, is a 60-story skyscraper completed in 1969. At 869 feet (259 m) tall, it is the eleventh-tallest building in Chicago, the tallest building inside the Chicago 'L' Loop elevated tracks, and the 40th-tallest in the United States. Chase Bank has its U.S. and Canada commercial and retail banking headquarters here. The building is also the headquarters of Exelon. The building and its plaza (known as Exelon Plaza) occupy the entire block bounded by Clark, Dearborn, Madison,