Europe’s attempts to appease Hitler failed, as Nazi Germany swallowed up Austria and Czechoslovakia by 1939. The straw that broke the camel's back, however, was Germany's invasion of Poland on September 1 of that year. Two days later, France and Great Britain declared war on Germany, and World War II had begun in earnest. Of course, as most people now know, the invasion of Poland was merely the preface to the Nazi blitzkrieg of most of Western Europe.The narrative is that the British stood alone in 1940 against the Nazi onslaught, defending the British Isles during the Battle of Britain and preventing a potential German invasion. At the beginning of 1941, it was unclear whether the Allies would be able to remain in the war for much longer. British Prime Minister Winston Churchill had already immortalized the men of the Royal Air Force with one of the West’s most famous war-time quotes, but the potential of a German invasion of Britain still loomed. The Allied victory in the Battle of Britain inflicted a psychological and physical defeat on the Luftwaffe and Nazi regime at large, and as the last standing bastion of democracy in Europe, Britain would provide the toehold for the June 1944 invasion of Europe that liberated the continent. For those reasons alone, the Battle of Britain was one of the decisive turning points of history’s deadliest conflict.