This simple activity encourages students to look at all the clues the cartoon provides, one at a time. As they work through them students discuss the nature of irony and then attempt to date the cartoon using their contextual knowledge. This proves a really good way of covering events from the beginning of the Truman Doctrine to the Berlin blockade. There are subtleties you might want to refer to (e.g. over Bulgaria and Yugoslavia) as well as the more obvious message. By keeping the date back, the students really have to think hard about the message of the cartoon IN CONTEXT. To accompany the self-explantory animated PowerPoint presentation there is a useful companion to studying political cartoons.