HMS Hood (pennant number 51) was a battlecruiser of the Royal Navy (RN). Hood was the first of the planned four Admiral-class battlecruisers to be built during the First World War. She was already under construction when the Battle of Jutland occurred in mid-1916, and that battle revealed serious flaws in her design; with drastic revisions, she was completed four years later. For this reason, she was the only ship of her class to be completed, as the Admiralty decided it would be better to start with a clean design on succeeding battlecruisers, leading to the never-built G-3 class. Despite the appearance of newer and more modern ships, Hood remained the largest warship in the world for 20 years after her commissioning, and her prestige was reflected in her nickname, "The Mighty Hood".

When war with Germany was declared, Hood was operating in the area around Iceland, and she spent the next several months hunting for German commerce raiders and blockade runners between Iceland and the Norwegian Sea. After a brief overhaul of her propulsion system, she sailed as the flagship of Force H, and participated in the destruction of the French fleet at Mers-el-Kebir. Transferred to the Home Fleet shortly afterwards, Hood was dispatched to Scapa Flow, and operated in the area as a convoy escort and later as a defence against a potential German invasion fleet. In May 1941, Hood and the battleship Prince of Wales were ordered to intercept the German battleship Bismarck and the heavy cruiser Prinz Eugen, which were en route to the Atlantic, where they were to attack convoys. On 24 May 1941, early in the Battle of the Denmark Strait, Hood was struck by several German shells, exploded, and sank with the loss of all but 3 of her crew of 1,418.