The document summarizes key events in the origins of the Cold War between 1945-1949:
1) Leaders from the USA, UK, and USSR met at the Yalta Conference in 1945 and agreed to divide Germany and Berlin into occupation zones, but disagreed on Poland's borders.
2) At Potsdam in 1945, the new leaders of the USA and UK disagreed with Stalin over reparations and the occupation of Japan.
3) Stalin ensured pro-Communist governments in Eastern Europe and interpreted the US's actions as a threat, leading to the Berlin Blockade in 1948.
4) The USA responded to the blockade by flying in supplies to West Berlin, and established NATO in