These were two crucial wartime conferences between the leaders of the 'Big Three' Allied powers.

The Yalta Conference was held in February 1945 and was attended by Roosevelt (USA), Churchill (UK), and Stalin (USSR).

At Yalta, the leaders planned the final defeat of Germany and agreed on a post-war plan that included dividing Germany into zones of occupation.

Stalin agreed to allow free elections in Eastern European countries, a promise he would later break.

The Potsdam Conference was held in July-August 1945, after Germany's surrender.

The attendees were Truman (who had replaced the deceased Roosevelt), Attlee (who had replaced Churchill after an election), and Stalin.

Tensions and mistrust between the Soviet Union and the Western powers were much more apparent at Potsdam.

Disagreements arose over the details of post-war governance and the amount of reparations Germany should pay.

During the conference, President Truman informed Stalin that the U.S. had successfully tested an atomic bomb.

These conferences shaped the post-war world but also revealed the deep divisions that would lead to the Cold War.