Hello. You did not enter the text to which this question refers, which makes it impossible for it to be answered accurately. However, I will try to help you in the best possible way.
It is only possible to answer your question by reading the text. However, we can consider that a text manages to reflect a society showing an impactful change that that society has experienced over time. In this case, the story you are referring to must have an element that represents a very strong and impacting social change that American society has. This element may be related to politics, the construction of the American economy, the status of world power, cultural diversity, democratic success, overcoming and resilience of the pioneers, among others.