Changes

The major tactical innovation of the war was the use of combined arms warfare, typified by the German doctrine of [[blitzkrieg]]. In this style of warfare armor, infantry, artillery and air power (see [[Luftwaffe]]) all coordinate to achieve overwhelming superiority at point on the enemy lines. Armor and fast-moving infantry units then exploit the gap and penetrate deep behind enemy lines. The objective is to cause a widespread collapse of the enemy's ability to fight. It was particularly effective during the early stages of the war, before the Allies developed effective countermeasures.

The major tactical innovation of the war was the use of combined arms warfare, typified by the German doctrine of [[blitzkrieg]]. In this style of warfare armor, infantry, artillery and air power (see [[Luftwaffe]]) all coordinate to achieve overwhelming superiority at point on the enemy lines. Armor and fast-moving infantry units then exploit the gap and penetrate deep behind enemy lines. The objective is to cause a widespread collapse of the enemy's ability to fight. It was particularly effective during the early stages of the war, before the Allies developed effective countermeasures.

On September 17, 1939, Poland was invaded from the east by Hitler’s ally, [[Josef Stalin|Stalin]].

On September 17, 1939, Poland was invaded from the east by Hitler's ally, [[Josef Stalin|Stalin]].

In 1939-1940, eastern Poland, [[Estonia]], [[Latvia]], [[Lithuania]] and [[Bessarabia]] were invaded and annexed by the Soviet Union.

In 1939-1940, eastern Poland, [[Estonia]], [[Latvia]], [[Lithuania]] and [[Bessarabia]] were invaded and annexed by the Soviet Union.