NEW : Official : 70 heads of state are coming to South Africa to honor Nelson Mandela . The official said the leaders will be in Johannesburg on Saturday and Sunday for a ceremony at which they will lay wreaths at Mandela's memorial site, where he was laid to rest last week. CNN 's Kim Norgaard and Catherine E. Shoichet contributed to this report from Atlanta . Services are held nationwide on a day of remembrance for Mandela . A state funeral will be held December 15 .
NEW : Official : 70 heads of state are coming to South Africa to honor Nelson Mandela . The official said the leaders will be in Johannesburg on Saturday and Sunday for a ceremony at which they will lay wreaths at Mandela's memorial site, where he was laid to rest last week. Services are held nationwide on a day of remembrance for Mandela . A state funeral will be held December 15 .