The Second World War was primarily caused by the rise of aggressive dictatorships in Germany, Italy, and Japan seeking to expand their territories through military conquest. The treaty of Versailles and the failure of the League of Nations also contributed to the growing tensions in Europe. The invasion of Poland by Nazi Germany in 1939 triggered the outbreak of the war, with the Axis powers (Germany, Italy, Japan) facing off against the Allied powers (mainly the United States, Soviet Union, and Great Britain). The war resulted in the loss of millions of lives, widespread destruction of cities and infrastructure, and the displacement of millions of people. The Holocaust, the systematic genocide of six million Jews by the Nazis, remains one of the most horrific events of the war. The war ended in 1945 with the defeat of the Axis powers, leading to the reshaping of the global political landscape and the creation of the United Nations to prevent future conflicts.
