Irony is most often defined as a contrast between expectations and realities in a circumstance. Throughout history there have been many examples of irony in a variety of different areas including politics, government, culture and media. Irony is often only recognized well after an original statement or occurrence since it often takes current perspectives to shed a greater light on a previous issue, statement or situation.
Now you have seen plenty of examples if irony in history. Looking back at what has happened in the past is always interesting. To learn about different types of irony, you can check out Examples of Irony.