and his sons Horace and William. Andrew Saks died in 1912 and his son Horace took over the company's management. In 1923, Saks & Co. merged with Gimbel Brothers, Inc., which was owned by a cousin of Horace Saks, Bernard Gimbel, operating as a separate autonomous subsidiary. On September 15, 1924, Horace Saks and Bernard Gimbel opened in the Saks Fifth Avenue Building at 611 Fifth Avenue, with a full-block avenue frontage south of St. Patrick's Cathedral, facing what would become Rockefeller Center. The architects were Starrett & van Vleck, who developed a design derived from classical architecture. When Bernard's cousin, Adam Gimbel, became president of Saks Fifth Avenue in 1926 after Horace Saks's sudden death, the company expanded, opening seasonal resort branches in Palm Beach, Florida, and Southampton, New York, in 1928. The first full-line year-round Saks store opened in Chicago, in 1929, followed by another resort store in Miami Beach, Florida. In 1938, Saks expanded to the West Coast, opening in Beverly Hills, California. By the end of the 1930s, Saks Fifth Avenue had a total of 10 stores, including resort locations such as Sun Valley, Idaho, Mount Stowe, and Newport, Rhode Island. More full-line stores followed with Detroit, Michigan, in 1940 and Pittsburgh, Pennsylvania, in 1949. In Downtown Pittsburgh, the company moved to its own freestanding location approximately one block from its former home on the fourth floor in the downtown Gimbel's flagship. The San Francisco location opened in 1952, competing locally with I. Magnin. BATUS Inc. acquired Gimbel Bros., Inc. and its Saks Fifth Avenue subsidiary in 1973 as part of its diversification strategy. More expansion followed from the 1960s through the 1990s including the Midwest, and the South, particularly in Texas. In 1990, BATUS sold Saks to Investcorp S.A., which took Saks public in 1996 as Saks Holdings, Inc. In 1990, the company launched "Saks Off 5th", an outlet store offshoot of the main brand, with 107 stores worldwide by 2016. In 1998, Proffitt's, Inc. the parent company of Proffitt's and other department stores, acquired Saks Holdings Inc. Upon completing the acquisition, Proffitt's, Inc. changed its name to Saks, Inc. 21st century In November 2001 the first Middle Eastern store opened at Kingdom Centre in Riyadh, Saudi Arabia. In August 2007, the United States Postal Service began an experimental program selling the plus ZIP code extension to businesses. The first company to do so was