At the Yalta Conference, President Franklin D. Roosevelt, Prime Minister Winston Churchill and Premier Joseph Stalin compete for postwar domination while meeting to discuss Germany and Europe's reorganization.

On Dec. 7, 1941, Japanese bombers attack Pearl Harbor and sink a large part of the U.S. Pacific Fleet; President Franklin D. Roosevelt decides it's time for the United States to strike back.

On June 22, 1941, Adolf Hitler launches a military offensive called Operation Barbarossa against the Soviet Union.

After Paris falls to the Nazis, French Prime Minister Henri Pétain plans to sign an armistice with Nazi Germany on June 16, 1940, but Gen. Charles de Gaulle secedes and rebels against the policy.

While the Wehrmacht crushes the allied armies in France, British officials prepare to face Adolf Hitler; on May 28, 1940, Prime Minister Winston Churchill finally convinces his colleagues to fight.