FILE - Flags adorn the grave of Confederate Lt. George Dixon, the commander of the Confederate submarine H.L. Hunley, in Charleston, S.C., in this Feb. 17, 2012, file photo. Monday, Feb. 17, 2014, is the 150th anniversary of the attack in which the Hunley sank the Union blockade ship Housatonic off Charleston, S.C., during the Civil War, becoming the first submarine in history to sink an enemy warship. (AP Photo/Bruce Smith, File)