Had the pleasure of working on the release of this compilation of Hugh Masekela's early work, which led to an invitation to the announcement at the South African embassy of Viva South Africa, a concert with Masekela, Miriam Makeba and Yvonne Chaka Chaka (which, unfortunately I couldn't go to). The three of them at the end of the presentation, unplanned, got up and sang Nkosi Sikelel i'Afrika. The significance of this being sung in the embassy was so powerful I think something got into my eye!
https://en.wikipedia.org/wiki/Stimela_(album)