2. September 3, 1939 – Hitler blitzkrieged Poland, and Russia attacked Poland from east. Hitler's troops invaded from north, south, and west. Poland awaited backup from Britain and France, but received very little. This marked the beginning of World War II. Because Britain and France both had pacts with Poland, they declared war on Germany.

3. The Battle of Britain
July 1, 1940 – “Operation Sea Lion” was Germany's strategy for attacking Britain. In the summer and fall of 1940, German and British air forces clashed in the skies over the United Kingdom, locked in the largest sustained bombing campaign to that date. A significant turning point of World War II, the Battle of Britain ended when Germany’s Luftwaffe failed to gain air superiority over the Royal Air Force despite months of targeting Britain’s air bases, military posts and, ultimately, its civilian population. Britain’s decisive victory saved the country from a ground invasion and possible occupation by German forces while proving that air power alone could be used to win a major battle.

5. Germany Invades the USSR
On June 22, 1941, Adolf Hitler launched his armies eastward in a massive invasion of the Soviet Union: three great army groups with over three million German soldiers, 150 divisions, and three thousand tanks smashed across the frontier into Soviet territory. The invasion covered a front from the North Cape to the Black Sea, a distance of two thousand miles. By this point German combat effectiveness had reached its apogee; in training, doctrine, and fighting ability, the forces invading Russia represented the finest army to fight in the twentieth century. Barbarossa was the crucial turning point in World War II, for its failure forced Nazi Germany to fight a two-front war against a coalition possessing immensely superior resources.

6. Japan Bombs Pearl Harbor

7. Bataan Death March April 9, 1942
After the surrender of the Bataan Peninsula on the main Philippine island of Luzon to the Japanese, the approximately 75,000 Filipino and American troops on Bataan were forced to make an arduous 65-mile march to prison camps. The marchers made the trek in intense heat and were subjected to harsh treatment by Japanese guards. Thousands perished in what became known as the Bataan Death March.

8. Battle of Stalingrad
The Battle of Stalingrad (July 17, 1942-Feb. 2, 1943), was the successful Soviet defense of the city of Stalingrad (now Volgograd) in the U.S.S.R. during World War II. Russians consider it to be the greatest battle of their Great Patriotic War, and most historians consider it to be the greatest battle of the entire conflict. It stopped the German advance into the Soviet Union and marked the turning of the tide of war in favor of the Allies. The Battle of Stalingrad was one of the bloodiest battles in history, with combined military and civilian casualties of nearly 2 million.

9. Germany Driven Out of North Africa
The British had been fighting the Germans and Italians in North Africa since Forcing Germany out of North Africa would provide the Allies with an opportunity to invade Italy. In May of 1943, George S. Patton defeated Rommel, and 240,000 Germans and Italians surrendered.

12. Victory in Europe Day
On May 8, 1945, both Great Britain and the United States celebrate Victory in Europe Day. Cities in both nations, as well as formerly occupied cities in Western Europe, put out flags and banners, rejoicing in the defeat of the Nazi war machine.

13. Atomic Bombs Dropped on Japan
President Harry S. Truman, warned by some of his advisers that any attempt to invade Japan would result in horrific American casualties, ordered that the new weapon be used to bring the war to a speedy end. On August 6, 1945, the American bomber Enola Gay dropped a five-ton bomb over the Japanese city of Hiroshima. Nagasaki was bombed 3 days later, prompting the surrender of the Japanese Empire.