The day the music died. I saw the Buddy Holly Musical when it was in Raleigh last year and it was quite good. What was interesting, and what I forgot), was that Waylon Jennings was supposed to be on that plane, but gave up his seat to the Big Bopper because the Big Bopper was sick. And Buddy Holly's guitarist was supposed to be on the plane but lost his seat in a coin toss to Valens.
Also, the way the musical played it, Holly's wife, who was pregnant at that time pleaded with him to not get on the plane that night, but he did anyhow. She miscarried a short time later. Tragic.