<P> Although Sears' naming rights expired in 2003, the building continued to be called the Sears Tower for several years . In March 2009, London - based insurance broker Willis Group Holdings agreed to lease a portion of the building, and obtained the building's naming rights . On July 16, 2009, the building was officially renamed Willis Tower . On August 13, 2012, United Airlines announced it would move its corporate headquarters from 77 West Wacker Drive to Willis Tower . </P> <P> In 2015, the Blackstone Group completed purchase of the tower for a reported $1.3 billion, the highest price ever paid for a U.S. property outside New York City . The new owners are considering several plans for further site developments . </P> <P> The Willis Tower observation deck, called the Skydeck, opened on June 22, 1974 . Located on the tower's 103rd floor, it is 1,353 feet (412.4 m) high, making it the highest observation deck in the United States and one of Chicago's most famous tourist attractions . Tourists can experience how the building sways on a windy day . They also can see far over the plains of Illinois and across Lake Michigan to Indiana, Michigan, and Wisconsin on a clear day . Elevators take tourists to the top in about 60 seconds, and allow tourists to feel the pressure change as they rise up . The Skydeck competes with the John Hancock Center's observation floor a mile and a half away, which is 323 feet (98.5 m) lower . Some 1.7 million tourists visit the Skydeck annually . A second Skydeck on the 99th floor is also used if the 103rd floor is closed . The tourist entrance can be found on the south side of the building along Jackson Boulevard . </P> <P> In January 2009, Willis Tower's owners began a major renovation of the Skydeck, including the installation of retractable glass balconies, which can be extended approximately 4 feet (1.2 m) from the facade of the 103rd floor, overlooking South Wacker Drive . The all - glass boxes, informally dubbed "The Ledge", allow visitors to look through the glass floor to the street 1,353 feet (412 m) below . The boxes, which can bear 5 short tons (4.5 metric tons) of weight, opened to the public on July 2, 2009 . However, on May 29, 2014, the laminated glass covering the floor of one of the glass boxes shattered while visitors were sitting on it, but caused no injuries . The broken glass was replaced within days, and tourist operations resumed as before . </P>

How many states can you see from the sears tower
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