1. Allegory: Definition
Allegory is a literary device in which characters or events represent or symbolize ideas and concepts.
Allegory functions in the same way an extended metaphor does, but an Allegory contains symbols that connect to specific people, ideas, events, etc, where a metaphor uses symbols that represent general/universal ideas.

2. Allegory: Definition
Allegories are usually implied, which means that if you are unaware of the story it connects to, the piece will make sense, but you may miss the underlying meaning.

3. Example Allegories
The Smurfs are allegorical of an ideal Marxist community
The Wizard of Oz is an allegory of the political undertones of 1890s Populism
Don McClean’s song, American Pie, is an allegory of the plane crash that killed Buddy Holly
The Crucible is an allegory of 1950s McCarthyism.

4. Allegory: Persuasive Value
Allegory uses parallel situations to show how two seemingly different stories are just alike.
Usually, one of the situation is extreme and well-known/simple to understand. The comparative situation may be less known or less understood, which allows the allegory to help the audience better understand the situation.