Answer: Big Three: Soviet Union leader Josef Stalin; U.S. President Franklin D. Roosevelt; and British Prime Minister Winston Churchill.
Explanation: The first meeting of the Big Three was in Tehran, Iran, on November 28, 1943, where some of the topics of the meeting were the preparation of invasions to Western Europe in the spring of 1944, invasion to South France, etc. Another meeting of the great three was in February 1945, at a conference in Yalta, where they discussed how to manage postwar in Europe.
