World War II: Operation Deadlight ends after scuttling 121 of 154 captured U-boats.

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.

Operation Deadlight was the code name for the Royal Navy operation of November 1945 – February 1946 to scuttle German U-boats surrendered to the Allies after the defeat of Germany near the end of World War II. After the surrender, political discussions continued between the Allies concerning the final disposal of the surviving German naval vessels, the result of which was an agreement to retain 30 U-boats in total, to be divided equally between the United Kingdom, the United States and the Soviet Union. The remainder would be scuttled.

U-boats are naval submarines operated by Germany, including during the First and Second World Wars. The term is an anglicized form of the German word U-Boot, a shortening of Unterseeboot. Austro-Hungarian Navy submarines were also known as U-boats.