The USS Arizona (BB-39) was commissioned on October 17, 1916, in the midst of World War I, and was one of the most powerful battleships in the world at that time. Initially assigned to the Atlantic Fleet, it was transferred to the Pacific Fleet in 1921. From the summer of 1929 to the spring of 1931, the Arizona underwent a major overhaul, during which it received, among other upgrades, more powerful guns and more stable fire control positions for the artillery officers. On December 7, 1941, during the Japanese attack on Pearl Harbor, the Arizona was hit by an 800 kg bomb and sank with a large portion of its crew. The ship was never recovered and still lies in the harbor today. A floating memorial, the USS Arizona Memorial, has been built above the sunken ship. Model with 2046 pieces, printed blocks, and movable elements.