ELI5: Explain Like I'm 5

World War II casualties

World War II was a very big war that happened between 1939 and 1945. It involved many countries around the world, and a lot of people died in it. A casualty means someone who dies in a war, so the World War II casualties mean the people who died in that war. Over 60 million people died in World War II, which is more people than there are in some countries.