Answer:
There were two alliances during the cold war: the Warsaw Pact and NATO
The initial countries that formed part of NATO (North Atlantic Treaty Org) were the USA, Canada, France, Britain, Benelux, Denmark, Iceland, Italy, Norway, Portugal, Greece, and Italy.
Most countries to the East of Europe fell under the Warsaw Pact of the USSR (1955) under communistic, Soviet control.
NATO was formed to protect Europe from a complete Soviet takeover (which the West believed would take place but never did) and was a military organization made up of militants from the countries mentioned above (countries who supported capitalism, democracy, and free enterprise)
Currently, there are 28 countries in NATO.