A visit to the Sears Tower Skydeck observation deck June 7, 2006, in Chicago. Completed in 1973, the Sears Tower at 1,450 feet tall is the tallest building in the U.S. and a popular location for tourists. 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 the Willis Tower.