World War II: Battle between HMAS Sydney and HSK Kormoran. The two ships sink each other off the coast of Western Australia, with the loss of 645 Australians and about 77 German seamen.

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.

On 19 November 1941, the Australian light cruiser HMAS Sydney and the German auxiliary cruiser Kormoran engaged each other in a battle off the coast of Western Australia. Sydney, with Captain Joseph Burnett commanding, and Kormoran, under Fregattenkapitän Theodor Detmers, encountered each other approximately 106 nautical miles off Dirk Hartog Island. The single-ship action lasted half an hour, and both ships were destroyed.

Nazi Germany, officially the German Reich and later the Greater German Reich, was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a totalitarian dictatorship. The Third Reich, meaning "Third Realm" or "Third Empire", referred to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which the Nazis referred to as the Thousand-Year Reich, ended in May 1945, after 12 years, when the Allies defeated Germany and entered the capital, Berlin, ending World War II in Europe.