Guard, and Citizen's Military Training Camps (CMTC). For a short while, from 1925 to 1928, the area was designated as "Camp Henry Knox National Forest." Air Corps use The post contains an airfield, called Godman Army Airfield, that was used by the United States Army Air Corps, and its successor, the United States Army Air Forces as a training base during World War II. It was used by the Kentucky Air National Guard for several years after the war until they relocated to Standiford Field in Louisville. The airfield is still in use by the United States Army Aviation Branch. Protection of America's founding documents For protection after the Japanese attack on Pearl Harbor in 1941, the Declaration of Independence, the Constitution of the United States and the Gettysburg Address were all moved for safekeeping to the United States Bullion Depository until Major W. C. Hatfield ordered their release after the D-Day Landings on 19 September 1944. Mechanized military unit occupation In 1931 a small force of the mechanized cavalry was assigned to Camp Knox to use it as a training site. The camp was turned into a permanent garrison in January 1932 and renamed Fort Knox. The 1st Cavalry Regiment arrived later in the month to become the 1st Cavalry Regiment (Mechanized). In 1936 the 1st was joined by the 13th to become the 7th Cavalry Brigade (Mechanized). The site quickly became the center for mechanization tactics and doctrine. The success of the German mechanized units at the start of World War II was a major impetus to operations at the fort. A new Armored Force was established in July 1940 with its headquarters at Fort Knox with the 7th Cavalry Brigade becoming the 1st Armored Division. The Armored Force School and the Armored Force Replacement Center were also sited at Fort Knox in October 1940, and their successors remained there until 2010, when the Armor School moved to Fort Benning, Georgia. The site was expanded to cope with its new role. By 1943, there were 3,820 buildings on . A third of the post has been torn down within the last ten years, with another third slated by 2010. 1947 Universal Military Training Experimental Unit In 1947, Fort Knox hosted the Universal Military Training Experimental Unit, a six-month project that aimed to demonstrate the feasibility and effectiveness of providing new 18-20 year-old Army recruits with basic military training