World War II: Allied aircraft unsuccessfully attacked a German destroyer in Førde Fjord, Norway.

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.

The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during World War II (1939–1945) to oppose the Axis powers. Its principal members were the "Big Four" – the United Kingdom, United States, Soviet Union, and China.

On 9 February 1945, near the end of the Second World War, a force of Allied Bristol Beaufighter aircraft suffered many losses during an attack on the German destroyer Z33 and its escorting vessels; the operation was called Black Friday by the survivors. The German ships were sheltering in a strong defensive position in Førde Fjord, Norway, forcing the Allied aircraft to attack through massed anti-aircraft fire (FlaK).

Z33 was a Type 1936A (Mob) destroyer built for the Kriegsmarine during World War II. Completed in 1943, the ship was damaged during the raid on the island of Spitsbergen in September and spent all of 1944 in Norwegian waters. She was damaged by British aircraft attacking the battleship Tirpitz in July. Z33 escorted troop convoys from northern Norway when the Germans began evacuating the area beginning in October. She ran aground in early 1945 as she was sailing for the Baltic and was badly damaged. While the ship was being towed to port for repairs, she and her escorts were attacked by Allied fighter-bombers. Z33 finally reached the Baltic in early April, but was reduced to reserve for lack of fuel. The ship was transferred to Cuxhaven and decommissioned shortly before the end of the war.