WARNING: This video contains archival footage from battlefields that some students may find disturbing. Teacher discretion is advised. The Cold War began after Europe was divided-up following World War II at the Yalta and Potsdam conferences, but ideological differences between capitalism and communism alienated former allies. The Truman Doctrine, the Marshall Plan, and the Berlin Blockade created greater distrust. A communist victory in China and the subsequent Korean War moved the focus of The Cold War to Asia, and with it the fear of the domino effect. Added to these conflicts were the space and arms Races, as the superpowers vied for supremacy. The nuclear deterrent kept them from open conflict, although each side exerted influence worldwide. When the Berlin Wall was erected in 1961, it seemed the threat of a world war would always exist.