Was a period of constant tension between US and USSR that lasted from 1948 to 1991.
There were 2 sides
Western bloc: Led by US and made up of countries in western europe and they colonial empires. Most of this countries had democratic governments and capitalist economy. They belong to NATO, that was a military alliance. Its objective was to protect Western bloc from the communist Eastern bloc. All of them were communist regimes. The communist countries were members of them Warsaw Pact (military alliance in response of NATO)
USA and USSR never declared the war on each other but they fought indirectly in Proxy wars (were wars fought between other countries, for example, the Korean war, the Vietnam war...