After the Second World War the Queen Mary was given a much needed refit before returning to commercial service. She resumed the North Atlantic run on 31 July 1947. She was finally united with her sister ship, RMS Queen Elizabeth, which had made her maiden voyage on 16 October 1946. Finally the two sister ships were together, marking a period of exceptional popularity and the start of their reign as Queens of the North Atlantic. However, by the late 1950s the popularity and convenience of air travel began to take its toll, seeing passenger numbers in decline. In December 1963 the Queen Mary began a series of cruises to try and find other profitable avenues, but to no avail. By April 1966 Cunard announced both the Queen Mary and the Queen Elizabeth were for sale. In July 1967 the Queen Mary was sold to the city of Long Beach, California for $3,450,000. The Queen Mary departed from New York for the last time on 22 September 1967. Following two final cruises the Queen Mary was laid up at Southampton. There, on 31 October 1967, she began her final sea voyage to Long Beach which would last 40 days and see her round Cape Horn off South America en-route to her new home.