Willis Tower of the four categories in 2004 to become recognized as the tallest building in the world. Taipei 101 surpassed the Petronas Twin Towers in spire height and the Sears Tower in roof height and highest occupied floor. The Sears Tower retained one record: its antenna exceeded Taipei 101's spire in height. In 2008, the Shanghai World Financial Center claimed the records of tallest building by roof and highest occupied floor. On August 12, 2007, the Burj Khalifa in Dubai, United Arab Emirates was reported by its developers to have surpassed the Sears Tower in all height categories. Upon completion, One
Center City Tower (Philadelphia) Center City Tower (Philadelphia) Center City Tower was the working name of a formerly proposed skyscraper in downtown Philadelphia. Designed and proposed by the firm now known as KlingStubbins (designers of Philadelphia's Penn Center and Bell Atlantic Tower), the building would have risen to a height of 1,050 feet (320 m) and 75 stories, making it the tallest building in The United States outside New York and Chicago, surpassing the height of the Bank of America Plaza in Atlanta. With a floor area of , it is one of the largest in Center City. The building was designed with an