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) and Monroe streets. Before the building was constructed, the Morrison Hotel, on its former site, was demolished in 1965. The building first opened in 1969 as First National Plaza. When constructed, it was the headquarters of First Chicago Corporation. In 1998, it became the headquarters for Bank One Corporation, and accordingly it was renamed Bank One Tower, The current name dates from October 24, 2005, after Bank One merged with Chase. Chase's retail bank division is based in the tower. Since May 2005 the National Public Radio show "Wait Wait... Don't Tell Me!" is taped on Thursday nights before a