<human>:  How did the Cold War play out?
<bot>: The Cold War was a period of geopolitical tension between the Soviet Union and the United States, and their respective allies, that lasted from 1947 to 1991. It began with the end of World War II and the Yalta and Potsdam conferences, in which the victorious Allies were divided between the two emerging superpowers. During this time, the two sides created a Cold War climate in which fear of nuclear attack and ideological differences shaped global politics and culture. The Cold War saw proxy wars fought in countries such as Vietnam and Korea, as well as numerous arms races, mutual espionage, and the use of sophisticated psychological warfare. After the collapse of the Soviet Union in 1991, the Cold War was declared officially over.