The major global conflict that occurred from 1939 to 1945 was World War II. This conflict involved numerous nations and can be characterized by its scale of devastation, global reach, and the ideologies at play, including fascism, communism, and democracy. It began with Germany's invasion of Poland and led to widespread battles across Europe, Asia, Africa, and the Pacific. The war resulted in unprecedented loss of life, the Holocaust, and widespread destruction. The outcome reshaped international relations, established the United States and the Soviet Union as superpowers, and set the stage for the Cold War.