World War II: Operation Compass: British and Indian troops under the command of Major-General Richard O'Connor attack Italian forces near Sidi Barrani in Egypt.

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 Compass was the first large British military operation of the Western Desert Campaign (1940–1943) during the Second World War. British metropolitan, Imperial and Commonwealth forces attacked the Italian and Libyan forces of the 10th Army in western Egypt and Cyrenaica, the eastern province of Libya, from December 1940 to February 1941.

General Sir Richard Nugent O'Connor, was a senior British Army officer who fought in both the First and Second World Wars, and commanded the Western Desert Force in the early years of the Second World War. He was the field commander for Operation Compass, in which his forces destroyed a much larger Italian army – a victory which nearly drove the Axis from Africa, and in turn, led Adolf Hitler to send the Afrika Korps under Erwin Rommel to try to reverse the situation. O'Connor was captured by an Italian reconnaissance patrol during the night of 7 April 1941 and spent over two years in an Italian prisoner of war camp. He eventually escaped after the fall of Mussolini in the autumn of 1943. In 1944 he commanded VIII Corps in the Battle of Normandy and later during Operation Market Garden. In 1945 he was General Officer in Command of the Eastern Command in India and then, in the closing days of British rule in the subcontinent, he headed Northern Command. His final job in the army was Adjutant-General to the Forces in London, in charge of the British Army's administration, personnel and organisation.