June 23 1990 / fromthearchive / Globe Staff photo by Barry Chin / Dancing to the finale music after his speech to an estimated 250,000 people at the Hatch Shell on Boston's Esplanade, Nelson Mandela is flanked by Sen. Edward Kennedy and Mayor Raymond Flynn. Musical performers included South Africa's Johnny Clegg & Savuka and Ladysmith Black Mambazo, as well as Paul Simon, Jackson Browne and Stevie Wonder. Local performers included the Boston rap group Young Nation, gospel singer Larry Watson, the Roxbury Presbyterian Choir, and soloist Linda Chorney.