Answer:
World War II was the biggest and deadliest war in history, involving more than 30 countries. Sparked by the 1939 Nazi invasion of Poland, the war dragged on for six bloody years until the Allies defeated Nazi Germany and Japan in 1945. Hitler's invasion of Poland in September 1939 drove Great Britain and France to declare war on Germany, marking the beginning of World War II. Over the next six years, the conflict would take more lives and destroy more land and property around the globe than any previous war.
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