Final answer:
The Yalta Conference increased tensions between the US and the Soviet Union, due to disagreements over Eastern Europe and Poland's future, laying the groundwork for the Cold War.
Step-by-step explanation:
The Yalta Conference significantly impacted relations between the United States and the Soviet Union. In February 1945, leaders from the US, UK, and the Soviet Union gathered in Yalta to shape the postwar world. President Franklin Delano Roosevelt, British Prime Minister Winston Churchill, and Soviet Premier Joseph Stalin discussed the division of Germany, the formation of the United Nations, and the future of Eastern Europe, particularly Poland. While they reached some agreements, such as dividing Germany into occupation zones and the Soviet promise to join the war against Japan, Stalin's insistence on a Soviet sphere of influence in Eastern Europe and the lack of clarity on Polish self-government led to increased tensions that would eventually contribute to the onset of the Cold War.