World War II: RMS Laconia, carrying civilians, Allied soldiers and Italian POWs is torpedoed off the coast of West Africa and sinks with a heavy loss of life.

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.

RMS Laconia was a Cunard ocean liner, built by Swan, Hunter & Wigham Richardson as a successor of the 1911–1917 RMS Laconia. The new ship was launched on 9 April 1921, and made her maiden voyage on 25 May 1922 from Southampton to New York City. At the outbreak of the Second World War she was converted into an armed merchant cruiser, and later a troopship. She was sunk in the South Atlantic Ocean on 12 September 1942 by U-156. Some estimates of the death toll have suggested that over 1,658 people were killed when the Laconia sank. Hartenstein staged a rescue of the passengers and the crew of Laconia, which involved additional German U-boats and became known as the Laconia incident.

A prisoner of war (POW) is a person held captive by a belligerent power during or immediately after an armed conflict. The earliest recorded usage of the phrase "prisoner of war" dates back to 1610.

The Laconia incident was a series of events surrounding the sinking of a British passenger ship in the Atlantic Ocean on 12 September 1942, during World War II, and a subsequent aerial attack on German and Italian submarines involved in rescue attempts. RMS Laconia, carrying 2,732 crew, passengers, soldiers, and prisoners of war, was torpedoed and sunk by U-156, a German U-boat, off the West African coast. Operating partly under the dictates of the old prize rules, the U-boat's commander, Korvettenkapitän Werner Hartenstein, immediately commenced rescue operations. U-156 broadcast her position on open radio channels to all Allied powers nearby, and was joined by several other U-boats in the vicinity.