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
Sears, Roebuck and Company Complex a modillioned cornice. It housed water tanks for firefighting on the upper levels, as well as offices and secretarial training facilities. It also housed the early broadcast facilities for WLS-AM. In 2015, it was refurbished and reopened to the public as the "John D. and Alexandra C. Nichols Tower". It now houses non-profit groups and offices, including a classroom on the 12th floor for the School of the Art Institute of Chicago. The Sears Roebuck plaque is still visible on top of the building. The Sears, Roebuck and Company Administration Building is a broad five-story masonry building, occupying about 3/4