The Big Three leaders of the main allied powers – President Franklin Delano Roosevelt for the United States, Prime Minister Winston Churchill for the British and Marshall Joseph Stalin for the Soviet Union – were in constant communication and held regular meetings throughout the second world war. The most important one came in the closing months, at the Crimean resort town of Yalta, on the Russian southern coast. There, the three men discussed the final steps against the Axis powers, and for the shape of postwar Europe.

On this day, February 4, in 1945, the week-long Yalta conference opened. The meetings were led by Stalin, whose armies by then were on the outskirts of Berlin and sweeping relentlessly westward. With nothing but the war-ravaged Western European forces in his path, Stalin rightly felt he could more or less dictate terms to his compatriots.

After Yalta, the Big Three would meet only once more, in Potsdam, Germany. There, Roosevelt was replaced by his successor, President Harry Truman, while Churchill was replaced halfway into the proceedings. One of the more interesting moments of the conference came in a brief aside between Truman and Stalin. Possibly intending to warn Stalin against unwarranted expansion, Truman informed him that the United States had developed a new kind of bomb, magnitudes more devastating than any ordinance used to that point. According to reports, Stalin was completely unperturbed, answering only that he hoped they would make good use of it against the Japanese.