Which country's invasion by Germany triggered World War II?

World War II is one of the most significant events in modern history, and understanding its origins is crucial. While tensions had been building in Europe for years, the event that directly sparked the war was Germany's invasion of Poland on September 1, 1939. This act of aggression by Nazi Germany, led by Adolf Hitler, prompted Britain and France to declare war on Germany two days later, on September 3rd. Poland was strategically important and had been subject to territorial disputes with Germany. Hitler's desire for "lebensraum," or living space, for the German people fueled his expansionist policies. The invasion involved a swift and brutal military campaign known as "blitzkrieg," or lightning war, which overwhelmed Polish defenses. While France and the UK were later involved, and the Netherlands was invaded later in the war, it was the invasion of Poland that served as the immediate trigger, setting off a chain reaction that engulfed the world in conflict. So, remembering Poland as the starting point of WWII is key.