which could also be used for conventional horizontal bombing and reconnaissance; dive bombers, also used for reconnaissance; and fighters for fleet defence and bomber escort duties. Because of the restricted space on aircraft carriers, these aircraft were almost always small, single-engined warplanes. The first true demonstration of naval air power was the victory of the Royal Navy at the Battle of Taranto in 1940, which set the stage for Japan's much larger and more famous attack on Pearl Harbor the following year. Two days after Pearl Harbor, the sinking of HMS Prince of Wales and HMS Repulse, marked the beginning of the end for the battleship era. Following WWII, aircraft carriers continued to remain key to navies throughout the latter 20th century, moving in the 1950s to jets launched from Supercarriers, behemoths which could displace as much as 100,000 tons. Submarines Just as important was the development of submarines to travel underneath the sea, at first for short dives, then later to be able to spend weeks or months underwater powered by a nuclear reactor. The first successful submarine attack in wartime was in 1864 by the Confederate submarine H.L. Hunley which sank the frigate . In both World Wars, submarines primarily exerted their power by sinking merchant ships using torpedoes, in addition to attacks on warships. All nations practiced unrestricted submarine warfare in which submarines sank merchant ships without warning, but the only successful campaign during this period was America's submarine war against Japan during the Pacific War. In the 1950s the Cold War inspired the development of ballistic missile submarines, each one loaded with dozens of nuclear-armed missiles and with orders to launch them from sea should the other nation attack. Aerial warfare The first use of airplanes in war was the Italo-Turkish War of 1911, when the Italians carried out several reconnaissance and bombing missions. During WWI both sides made use of balloons and airplanes for reconnaissance and directing artillery fire. To prevent enemy reconnaissance, some airplane pilots began attacking other airplanes and balloons, first with small arms carried in the cockpit, and later with machine guns mounted on the aircraft. Both sides also made use of aircraft for bombing, strafing and dropping of propaganda leaflets. The German air force carried out the first terror bombing raids, using Zeppelins to drop bombs on Britain. By the end of the war airplanes had become specialised into bombers, fighters,