For example, the film Zootopia is seen as an allegory for modern race relations. The amplified rhetoric of the characters regarding the behavior of former "predators" toward "prey" and the resulting distrust is mirrored broadly in today's society.
Dr. Seuss used allegory regularly in "The Sneetches" (about race relations as well as the lenghts that some will go to to fit in) and "The Butter Battle Book" (about the nuclear standoff between Russia and the United States).
A key to allegory: The story never explicitly states that it is an allegory or may have a second meaning. The author trusts that you will figure it out and begin to think through all the parallels.
For homework, type a brief piece of writing which is an allegory. For example, one student wrote about the behavior of a pride of lions last year. There were just enough clues in the piece to lead me to know that it was actually about social cliques and bullying. Indeed, lions hunt in loyal packs.