World War II: General Władysław Sikorski becomes prime minister of the Polish government-in-exile.

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.

Władysław Eugeniusz Sikorski was a Polish military and political leader. Before World War I, Sikorski established and participated in several underground organizations that promoted the cause of Polish independence. He fought with distinction in the Polish Legions during World War I, and later in the newly created Polish Army during the Polish–Soviet War of 1919–1921. In the latter war, he played a prominent role in the decisive 1920 Battle of Warsaw.