If you'd asked me the rather odd question, "What is the greatest song you know that's about the performance of some other song?", up until recently I'd have said, "It's Eric Bogle's 'And the Band Played Waltzing Matilda,' of course."
But I may have found its match for power and impact.
It's a fairly new song, about the memorial for the victims of the Charleston shooting, it's written by Zoe Mulford, and it's performed here by the incomparable Joan Baez.
The title is "The President Sang Amazing Grace." You might think that an unpromising phrase for a song lyric. You'd be wrong.