Why did they use the iron curtain?

Answer 1

The "iron curtain" is a figure of speech. There wasn't an actual curtain made from iron. It comes from an address by Winston Churchill. Here is the important part: I have a strong admiration and regard for the valiant Russian people and for my wartime comrade, Marshal Stalin. There is deep sympathy and goodwill in Britain -- and I doubt not here also -- toward the peoples of all the Russias and a resolve to persevere through many differences and rebuffs in establishing lasting friendships. It is my duty, however, to place before you certain facts about the present position in Europe. From Stettin in the Baltic to Trieste in the Adriatic an iron curtain has descended across the Continent. Behind that line lie all the capitals of the ancient states of Central and Eastern Europe. Warsaw, Berlin, Prague, Vienna, Budapest, Belgrade, Bucharest and Sofia; all these famous cities and the populations around them lie in what I must call the Soviet sphere, and all are subject, in one form or another, not only to Soviet influence but to a very high and in some cases increasing measure of control from Moscow. The safety of the world, ladies and gentlemen, requires a unity in Europe, from which no nation should be permanently outcast. It is from the quarrels of the strong parent races in Europe that the world wars we have witnessed, or which occurred in former times, have sprung.