Little history
Engineers toyed with the idea of a sea-going vessel that could submerge itself completely for quite some time before the first true submarine was ever successfully tested. Today, the submarine forms an important cog in the control of the seas for any nation and has since taken the mantle of "King of the Seas" from the equally-important aircraft carriers. Aircraft carriers came into their own during World War 2, rendering the previously impervious battleship utterly useless in the wake of torpedo aircraft and dive bombers. Likewise, the undetectable nature of the submarine soon rendered the aircraft carrier a juicy target where a submarine could make its way through fleet defenses and ultimately sink thousands of sailors and airmen in one swoop. The submarine certainly proved its worth in World War Two, particularly in the hands of the German Navy, where her U-Boats nearly destroyed any outside support for the United Kingdom.