Operation Barbarossa--the largest land invasion ever mounted--sent 3 million German troops and 3,300 tanks into the Soviet Union.

Defeated at Stalingrad and denied entry to Moscow, the Wehrmacht embarked on a two-year delaying action as it retreated to Germany.

Follow the preparations for D-Day and the course of the war in Europe after the successful invasion.

As Germany was squeezed in the vice of the Allied advance, the Big Three met at Yalta to plan for the aftermath of war.