JOHANNESBURG, SOUTH AFRICA - DECEMBER 03:  Prince Harry in Nelson Mandela's office with Graca Machel his widow at the Nelson Mandela Foundation Centre of Memory on December 3, 2015 in Johannesburg, South Africa.  Prince Harry is visiting South Africa as part of a Royal Tour that has included the Opening of a new Charity Centre for children in Lesotho (Sentebale's Mamohato Children's Centre) and includes stops in Durban, Cape Town, Kruger National Park and Johannesburg.  (Photo by Chris Jackson/Getty Images)