What happened
Franklin Roosevelt, Winston Churchill, and Joseph Stalin met at Yalta to discuss occupation zones, the future of eastern Europe, the United Nations, and the final defeat of Nazi Germany.
Why it matters
Yalta sits at the hinge between wartime alliance and postwar rivalry. It belongs in this timeline because it shows that the war's end was also the beginning of a new geopolitical settlement shaped by the coming bipolar order.
Notes
This is the clearest conference anchor for the war-to-Cold War transition.