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
Park Tower (Chicago) on the prestigious Magnificent Mile, Park Tower is also home to the acclaimed restaurant NoMi. Park Tower (Chicago) Park Tower is a skyscraper located at 800 North Michigan Avenue in Chicago, Illinois. Completed in 2000 and standing at tall with 70 floors — 67 floors for practical use, it is the twelfth-tallest building in Chicago, the 43rd-tallest building in the United States, and the 83rd-tallest in the world by architectural detail. It is one of the world's tallest buildings to be clad with architectural precast concrete (the Transamerica Pyramid Building in San Francisco is taller). It is one of the