World War II was one of the most important events in human history, and there are many known facts about it. However, there are some lesser-known or unknown facts about war.

• The Soviet Union suffered the most casualties during the war, with an estimated 27 million dead.
• The first German soldier killed during the war was killed by the Japanese, not by the Allies.
• During the war, the United States tried to buy Greenland from Denmark for strategic reasons, but Denmark refused to sell it.

• The famous "V for Victory" sign was first used in Belgium by the Belgian politician Victor de Lavraie as a symbol of resistance to the Nazi occupation. Japan planned to invade the US mainland in 1945, but the plan fell through after the US victory at the Battle of Midway.
• More than 400,000 German prisoners of war were interned in the United States during the war, some of them used to work on American farms and factories.
• After the war, the United States and the Soviet Union planned to invade Japan, but Japan surrendered.

• The Royal Air Force dropped over 1.5 million of her leaflets over Germany during the war, calling on German soldiers to surrender.
• During the war, the United States developed a top-secret project to create a "bat bomb" that would shoot incendiary bats at Japanese cities. The only battle fought on the American mainland during the war was the Battle of Attu in Alaska's Aleutian Islands.

These are just a few of the many little-known facts about World War II, but highlight the complexity and significance of this historical event.