Final answer:
World War II began on September 1, 1939, with Germany's invasion of Poland, utilizing blitzkrieg tactics. This led Britain and France to declare war on Germany, marking the commencement of the global conflict.
Step-by-step explanation:
Germany's invasion of Poland:
World War II began on September 1, 1939, when Germany invaded Poland. This date marks the start of a conflict that would engulf the world for the next six years.
The invasion was sudden and powerful, showcasing the devastating potential of Hitler’s blitzkrieg tactics. Utilizing a combination of airpower with the Luftwaffe and ground forces including tanks and infantry, the German military overwhelmed Polish defenses. Despite brave resistance, Poland was quickly encircled, and after a month of fighting, the nation fell to the German invaders on September 27, 1939. The aggression against Poland prompted Britain and France to declare war on Germany, thus formally beginning World War II. The Soviet Union, as per a secret agreement in the Molotov-Ribbentrop Pact, invaded Poland from the east on September 17, 1939, further sealing Poland’s fate. The event demonstrated Germany’s military might and set the stage for subsequent expansion across Europe. This day in history is significant as it represents the start of what would be a truly global conflict, which had profound and lasting impacts on the international order and the geopolitical landscape.