Iron Curtain
The "Iron Curtain" was the boundary which symbolically, ideologically, and physically divided Europe into two separate areas from the end of World War II until the end of the Cold War, roughly 1945 to 1991. The first recorded use of the term was in 1920 by Ethel Snowden in her book 'Through Bolshevik Russia'. German politician Lutz Graf Schwerin von Krosigk was the first to refer to an "Iron Curtain" coming down across Europe after World War II, although he borrowed the expression from Joseph Goebbels.[1] The term was not widely used until March 5, 1946, when it was popularised by Winston Churchill in his 'Sinews of Peace' address.
Fourth Wall
The fourth wall is the imaginary invisible wall at the front of the stage in a proscenium theater, through which the audience sees the action in the world of the play. The concept is generally presumed to have originated in nineteenth century theatre with the advent of theatrical realism. Critic Vincent Canby described it in 1987 as "that invisible scrim that forever separates the audience from the stage."
