The iron curtain is portrayed as a literal shower curtain in this image. In real life, it was a line of defense along the border between East and Western Europe. The West which was soviet controlled, still suffered from the effects of WW2, while the East prospered with help from the U.S.
The arms race was when the United States and the Soviet Union tried to one up each other with weaponry. They threatened to use progressively stronger weapons and created nuclear bombs as the war progressed.
The Hollywood Ten was a group of producers, writers, and directors who were accused of participating in communistic activities. They refused to answer questions and were sent to prison for contempt of Congress. This ruined their careers by putting them on a blacklist.