World War II was the deadliest and most destructive war in history. The battle resulted in an estimated 50 to 85 million civilian and military casualties over six years.
Countries that suffered the most casualties include China, Germany and the Soviet Union. The war pitted the Allies – China, Great Britain, the Soviet Union and the United States – against Germany, Italy and Japan, the Axis powers. World War II was ignited by Adolf Hitler's 1939 invasion of Poland and ended with surrender from Germany and Japan in 1945. The war involved roughly 70 million soldiers from more than 30 countries worldwide.