What is the best prequel of all time?

Could you please elaborate on your opinion of the best prequel of all time? What specific elements of the story, characters, or filmmaking do you believe make it stand out as the ultimate prequel? Are there any other prequels that you think come close, and if so, what separates the one you've chosen from the rest? Additionally, how do you think the prequel you've chosen has impacted the larger narrative or franchise it belongs to?