Submarines have a long history in the United States, beginning with Turtle, during the American Revolution. The world’s first combat submarine, invented by David Bushnell, was devised as a means of breaking the British blockade of Boston Harbor but was unsuccessful on multiple attempts. The U.S. Navy officially joined the undersea world when it purchased USS Holland (SS 1) on 11 April 1900, and commissioned her on 12 October 1900. The boat, designed by John P. Holland, proved valuable for experimental purposes during her 10-year career. Since then submarines have evolved dramatically, but remain a vital part of the American Fleet. (Naval History and Heritage Command / Daniel Garas)