On April 11, 1900, the United States Navy quietly acquired a strange, torpedo-shaped vessel that would alter the nature of sea power for generations to come. It was not a battleship or a cruiser. It had no tall masts or broad decks. It did not fly into battle under a banner of cannon smoke and gallant brass. But it changed everything. That vessel, the privately built Holland VI, would become USS Holland, the first modern submarine commissioned by the U.S. Navy. Her acquisition on that date is now honored as the official birthday of the United States Navy Submarine Force.