The term Iron Curtain was used as early as 1819 to describe an impenetrable barrier. It began to be used in the 1920s to describe the extent of the Soviet Union's political influence. Then during the Second World War Hitler's propaganda minister Joseph Goebbels popularized the term. Its use was made crystal clear to a much wider audience when Winston Churchill described the Iron Curtain in a famous quote in 1945. He said that 'From Stettin in the Baltic to Trieste in the Adriatic an iron curtain has descended across the continent.' This barrier to trade and the free passage of people was based on political ideas but made concrete in the form of strong border defences between countries on one side of it or another. This was seen most clearly in Berlin with the infamous Berlin Wall.
