Second World War: The German battleship Bismarck sank the British battlecruiser Hood at the Battle of the Denmark Strait.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

Bismarck was the first of two Bismarck-class battleships built for Nazi Germany's Kriegsmarine. Named after Chancellor Otto von Bismarck, the ship was laid down at the Blohm & Voss shipyard in Hamburg in July 1936 and launched in February 1939. Work was completed in August 1940, when she was commissioned into the German fleet. Bismarck and her sister ship Tirpitz were the largest battleships ever built by Germany, and two of the largest built by any European power.

HMS Hood 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".