A song playing comprises a very specific and vivid set of memory cues. Because the multiple-trace memory models assume that context is encoded along with memory traces, the music that you have listened to at various times of your life is cross-coded with the events of those times. That is, the music is linked to events of the time, and those events are linked to the music.
Daniel J. Levitin (2006). “This Is Your Brain on Music: The Science of a Human Obsession”, p.175, Penguin