From November 28 to December 1, 1943, the leaders of the "Big Three" Allied countries—U.S. President Franklin D. Roosevelt, Soviet Premier Josef Stalin, and British Prime Minister Winston Churchill—met in Tehran, the capital of Iran, to plan their strategy for the war. At this conference, the three leaders agreed to open a second front against the Nazis by the summer of 1944. This plan resulted in the massive invasion of occupied France on D-Day, June 4, 1944. Later conferences in Yalta and Potsdam decided the territorial make-up of the post-war world.
