U.S. first lady Michelle Obama, second left, visits the Nelson Mandela Foundation in Johannesburg, South Africa, Tuesday, June 21, 2011. Pictured from left to right: Sello Hatang of the Nelson Mandela Foundation; Mrs. Obama; mother Marian Robinson; Nelson Mandela’s wife Graca Machel, Michelle Obama’s daughters Sasha Obama and Malia Obama. (AP Photo/Charles Dharapak, Pool)