What was World War 2?

World War 2 started when Adolf Hitler and the Nazis invaded Poland on September 1, 1939. Poland declared war on Germany, which means that Britain and France also declared war on Germany because they were allies. On December 7 1941, Japan bombed the U.S. Naval base known as Pearl Harbor. This brought the United States into the war and declared war on Japan. After this, the Allies started gaining momentum. On June 6, 1944 known as D-Day, the Allies invaded northern France and defeated the German troops in France. On July 11, 1945 the United States dropped an atomic bomb on the Japanese cities of Hiroshima and Nagasaki. Japan surrendered on the date of September 2, 1945.