June 23 1990 / fromthearchive / Globe Staff photo by John Tlumacki / Spectators greeted the limousine carrying Nelson Mandela on Martin Luther King Boulevard. During a whirlwind tour through Roxbury and Dorchester, the Mandelas were welcomed as heroes. Thousands lined the streets and waved the ANC's black, green and gold flag. Others placed pictures of the Mandelas in their windows.