Second World War: The German ocean liner Cap Arcona, afloat in the Bay of Lübeck with thousands of concentration camp survivors on board, was attacked and sunk by the Royal Air Force.

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.

SS Cap Arcona, named after Cape Arkona on the island of Rügen, was a large German ocean liner, later a requisitioned auxiliary ship of the Kriegsmarine, and finally a prison ship in the later months of World War II (1939–1945). A flagship of the Hamburg Südamerikanische Dampfschifffahrts-Gesellschaft, she made her maiden voyage on 29 October 1927, carrying passengers and cargo between Germany and the east coast of South America, and for a brief period of time she was the largest and fastest ship on the route, until one month later she was surpassed on the same Europe-South America route by the Italian liner MS Augustus.

The Bay of Lübeck is a basin in the southwestern Baltic Sea, off the shores of the German states of Mecklenburg-Vorpommern and Schleswig-Holstein. It forms the southwestern part of the Bay of Mecklenburg.

From 1933 to 1945, Nazi Germany operated more than a thousand concentration camps, including subcamps on its own territory and in parts of German-occupied Europe.