it was interesting to see a documentary on World War II recently, and a key summit of Allied leadership was a meeting of Roosevelt, Churchill and Stalin in Tehran. They used the royal palace there for photo ops quite a lot.
I, showing my lack of education, first learned of the conference from reading 'War and Remembrance', Herman Wouk. It's amazing how much legitimate history he crammed into it and its prequel, 'The Winds of War.'
https://en.wikipedia.org/wiki/Tehran_Conference