United States
If you're referring to the barrier that separated communist countries in Europe from non-communist countries, the answer is the Berlin Wall.
Non-Communist actually, today no one really cares whose communist or not; as long as they're not hurting anyone (warring on some other nation). Britain, Japan, Australia, nearly all of the Americas (North, Central, and South) are non-communist nations.
Communist NORTH Korea's enemies are mostly non-communist countries.
The Iron Curtain
All European countries are non-communist, so you merely need to list four Western European countries. Germany, Italy, France, and Ireland are such four.
There were too many countries around the world to name to answer your question. It would be easier to name the communist countries and then you can figure out which countries around the world were not communist countries. These were the communist countries: China, North Korea, The Soviet Union and all its captured countries from World War 2 such as Czecholovakia, Romania, Hungary, Yugoslavia, the Baltic Nations, Lithuania, and others. Later Viet Nam became a communist country when the North Vietnamese defeated South Viet Nam. Most of the non-communist countries became part of the United Nations so you can look on the history of their list of countries.
As of now, there are no countries in the Caribbean area that are governed by a communist political system. Some countries in the Caribbean have socialist parties or elements in their government, but none are strictly communist.
Russia
Today, all European countries are non-communist. However, during the Cold War, the Non-Communist countries in Europe included: - Iceland - Ireland - United Kingdom - Portugal - Spain - Andorra - France - Monaco - Malta - Vatican City - San Marino - Italy - Austria - Liechtenstein - Switzerland - Luxembourg - Belgium - Netherlands - West Germany - Denmark - Norway - Sweden - Finland - Greece - Turkey - Cyprus
Presently, some communist countries include North Korea, China and Cuba.one example is North Korea, if you wanted to know one. China--sort of
No, it is not illegal to be a communist in any country, but some countries may have restrictions or limitations on communist activities.
Yes, the term "iron curtain" was coined during the cold war to describe the division between the Communist Soviet Union and the rest of Europe.