04 February 1945,
The Jalta Historic Conference begins between the Soviet Union, the United Kingdom and the United States. II. At the end of the World War, Stalin, Churchill and Roosvelt met to represent the countries mentioned, respectively. It discussed the military strategy to win the war, which area of occupation would be allocated to each defeated army in Germany, the situation in Poland and the creation of the UN, among others. The President of the United States, Roosvelt, died two months later, and his successor Truman, obsessed with the Communists, did not speak. It is taken as the starting point of the Cold War.
Source:
Josep Fontana, for the sake of empire. A history of the world since 1945 (Ed. Past & Present).