During the administration of United States President John F. Kennedy, the Cold War reached its most dangerous state, and the United States and the Union of Soviet Socialist Republics (USSR) came to the edge of nuclear war in what was known as the Cuban Missile Crisis. What was the Cold War? What started the tensions between the United States and the USSR? What actions were taken and how were the problems resolved? All of these questions and more shall be answered in this paper. The Cold War was a struggle between the United States and its allies and the Soviet Union. Although direct military conflict never took place, diplomatic and economic struggles occurred.