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
Elgin Tower Building 1999 to showcase its architectural merit. Stickling died later that year, but his benefactors transferred the building to the William R. Stickling Charitable Foundation, who currently maintain the building. An addition was built in 1999 to house, rent-free, the Downtown Neighborhood Association, who intend to revitalize the downtown area. The tower was added to the National Register of Historic Places on May 22, 2002. The Elgin Tower Building is located at 100 E. Chicago St. in Elgin, between Douglas and N. Grove Avenues. This area has historically been known as Fountain Square, generally accepted as the downtown area of Elgin.