The Cold War was a period of political and military tension between the United States and Soviet Union from 1945 to 1991. Though they never directly fought each other, there was a constant rivalry as each country sought to spread their opposing economic and political ideologies across the world. This included the US aiming to contain the spread of communism and rebuild democratic allies through programs like the Marshall Plan, while the Soviets wanted to promote communism and control Eastern European governments as a buffer against Western influence. Their conflicting goals led to an arms race, proxy wars, and the division of Europe and Germany between capitalist and communist spheres of influence marked by the Iron Curtain.