The following outline is provided as an overview of and topical guide to World War II: World War II, or the Second World War – global military conflict from 1939 to 1945, which was fought between the Allied powers of the United States, United Kingdom, and Soviet Union against the Axis powers of Germany, Italy, and Japan, with their respective allies. Over 60 million people, the majority of them civilians, were killed, making it the deadliest conflict in human history.