The document discusses Adolf Hitler and Nazi Germany's aggression leading up to World War II. It describes Hitler's rise to power in Germany and annexation of Austria and Czechoslovakia. It then covers Germany's invasion of Poland on September 1, 1939, which marked the beginning of World War II, as well as Germany's quick defeat of France and other countries using its "Blitzkrieg" tactics in 1940, leaving Britain as the only remaining opponent facing Nazi Germany in Europe.