Despite a massive increase in anti-air defence systems during the Second World War, battleships were not adequately protected against attacks by aircraft. Developments in air warfare combined with the emergence of powerful carrier forces relegated battleships to a secondary status. This fact was shown several times early in the war: a British attack on moored battleships at Taranto, Italy (1940CE); the sinking of the German battleship Bismarck (1941CE), which succeeded when antiquated British biplanes dropped the torpedoes which disabled the ship's rudders; the Japanese attack on Pearl Harbor and the Japanese sinking of the British battleship Prince of Wales off the coast of the Malayan Peninsula (1941CE)); as well as the sinking of the Japanese battleship Musashi in the Philippines (1944CE). Thereafter, most of the naval action of the Second World War involved the use of battleships either in defensive capability (ie the Soviet defence of the Baltic) or as fire support, with carrier aircraft duels being the main form of naval combat, especially in the Pacific theatre. So afterwards, most WW2-era battleships were largely scrapped, with cruisers, frigates and destroyers now forming the core of most modern militaries.
Even so, the concept of an "advanced battleship", ie a massively armoured warship boasting the most firepower, still survived somewhat with regards to the Soviet Navy. From the Second World War onwards to the present day, the Russian Navy has maintained a plethora of ship types classified as "battlecruisers", of which the Kirov class is still in commission (represented by Admiral Nakhimov and Pyotr Veliky). These warships somewhat continue the tradition of large and powerful vessels meant to overwhelm land and sea targets with a vast complement of cruise missiles, while maintaining a comfortable degree of protection for the ship in the form of SAM missiles.