Naval warfare has evolved since the days of the old wood-and-sail creations that dotted the oceans. Once iron became a viable protection scheme, the ironclad was born and this forever changed the warplanner's approach to naval combat - particularly as seen in the American Civil War. From this evolution sparked a new one shortly thereafter as the steel capital ship was born and, from this, the all-big-gun, steam-powered vessels came into being. The battleship reigned over the high seas for a good part of modern naval history until supplanted by the aircraft carrier in World War 2 (1939-1945). Alongside this development was the submarine which graduated from the limited diesel-electric types to nuclear-powered models capable of indefinite range and long-range attacks.