Willis Tower new competition by retailing giants such as Kmart, Kohl's, and Walmart. The fortunes of Sears & Roebuck declined in the 1970s as the company lost market share; its management grew more cautious. Nor did the Sears Tower draw as many tenants as Sears had hoped. The tower stood half-vacant for a decade as a surplus of office space was erected in Chicago in the 1980s. In 1990, the law firm of Keck, Mahin & Cate decided to move out of its space in the Sears Tower and into a development that would become 77 West Wacker Drive, rebuffing Sears' attempts
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