The Tehran Conference was the first time the Big Three met up for some serious talks. The summit, which was codenamed Eureka, took place between 28 November and 1 December 1943. It saw Joseph Stalin, Franklin D. Roosevelt and Winston Churchill discuss coordination of the war effort against Nazi Germany and in particular the coordination of D-Day with the Soviet war effort.
Soviet entry into the war against Japan and the setting up of the United Nations in the post-war world were also discussed at the conference, which took place in the Soviet Union’s embassy in Tehran (hence the name). Lucky for you, that’s all you need to know!