World War II was the last time that battleships ruled the U.S. Navy. It was also the last time that large numbers of merchant ships and luxury liners were used as troop transports. Two of the most famous ships from that war are the USS Missouri and the Queen Mary.
After WWII, aircraft carriers replaced battleships as the lead vessels on missions because of their size and versatility. Having a ship that could sail to within air-range of a target, then launch fighter aircraft was considered advantageous.
The last battleship left afloat, the USS Missouri, was decommissioned on March 31, 1992. The ship was moored at Pearl Harbor in Honolulu, Hawaii, and was destined to become the Battleship Missouri Memorial. It sits across from the USS Arizona Memorial, dedicated to those who died on Dec. 7, 1941. America's military involvement in World War II began with that attack. It ended when the Japanese formally surrendered to General MacArthur on the deck of the Missouri on Sept. 2, 1945.
Another high-profile ship that served during World War II is the luxury liner, the Queen Mary. The entire ship was painted gray, and posh cabins were turned into troop quarters. By the time the war ended, the Queen Mary had transported 765,429 military troops and sailed over 569,429 miles, all under threat of sinking by German U-boats. Today the Queen Mary is permanently moored in Long Beach. The ship is decked out in all its finery and doubles as a museum and hotel.