[Kiwiwriter]

1. Nazi-Soviet Non-Aggression Pact: this truce between two bitter enemies, Nazism and Communism, enabled Hitler to invade Poland and then the West without having to worry about watching his back. In addition, the Soviets obediently provided Hitler with supplies, and were allowed to gobble up Eastern Poland, the Baltic States, and a piece of Romania.
2. German invasion of Poland, September 1939. Germans conquered the nation in less than a month. Their use of air power, armor, and mobile warfare impressed and shocked other nations, but apparently had little impact on the French. The invasion was followed by colossal butchery: millions of Poles and Jews were slaughtered in concentration camps.
3. Dunkirk, May 1940. The British successfully evacuated their two corps of troops and French forces under German attack and air bombardment. Saving the force gave Britain a manpower reserve to defend itself against invasion and the nucleus of the army that invaded France in 1944. The British nation as a whole went out to save their troops in the famous “Little Ships.” The evacuated troops left behind their arms and equipment, but the battle was a moral victory for the British, as they came together as never before, determined to fight behind Churchill.
4. Battle of Britain, August-October 1940. First major defeat for Germany. Luftwaffe fails to gain air superiority over British soil, which forces Hitler to cancel plans to invade the British Isles. Hitler’s line of easy victories comes to an end. Next stop: Russia.
Lend-Lease Act: This enabled America to supply arms and equipment to the British without them paying for it. That in turn enabled Britain and other allies (Russia and France, later) to re-equip their forces, in the Soviet case, after huge losses in battle, in the French case, to modernize after Torch. Lend-Lease also led to standardization of Allied war effort and its logistics chain – all Allied powers used American jeeps, trucks, halftracks, tanks, jerricans, and so on.