The Cold War began after WWII as tensions rose between the US and USSR over differing political and economic ideologies. The USSR sought to increase its security and spread of communism while the US aimed to promote democracy and capitalism. This led to divisions in Europe with the Iron Curtain and an arms race between the two superpowers as each sought to contain the influence of the other through policies like containment and deterrence using nuclear weapons. During the 1950s, conflicts in Korea and fears of communist subversion at home exacerbated Cold War tensions.