A prostitute in Johannesburg waits for a client on a street corner. An estimated two-thirds of sex workers in South Africa are HIV positive. Yoav Lemmer/AFP/Getty Images hide caption

itoggle caption Yoav Lemmer/AFP/Getty Images

A nurse takes a blood sample from Nkosi Minenhle, 15, in a mobile clinic set up to test students for HIV at Madwaleni High School in KwaZulu Natal, South Africa. Stephane de Sakutin/AFP/Getty Images hide caption

itoggle caption Stephane de Sakutin/AFP/Getty Images

Zimbabwe's President Robert Mugabe (left) greets South African President Nelson Mandela in Harare, Zimbabwe, in 1998. The two men have shaped their countries in dramatically different ways. Rob Cooper/AP hide caption

itoggle caption Rob Cooper/AP

A well-wisher uses his phone to take a picture of a banner of photos of Nelson Mandela outside the Mediclinic Heart Hospital in Pretoria, where the former South African president is being treated. Ben Curtis/AP hide caption

itoggle caption Ben Curtis/AP

Schoolchildren sing 'Happy Birthday' to former South African President Nelson Mandela at Phefeni High School, opposite Mandela's former home in Soweto Township on Thursday in Johannesburg, South Africa. Christopher Furlong/Getty Images hide caption

itoggle caption Christopher Furlong/Getty Images

On the eve of Nelson Mandela's 95th birthday, street vendors in Pretoria, South Africa, were selling T-shirts to mark the occasion. Madiba is Mandela's tribal name. Christopher Furlong/Getty Images hide caption

itoggle caption Christopher Furlong/Getty Images

A woman waits to get AIDS drugs on April 8 at a clinic in Ga-Rankuwa, South Africa, about 55 miles north of Johannesburg. New WHO guidelines say patients should start HIV treatment much earlier, before they become extremely sick. Stephane de Sakutin/AFP/Getty Images hide caption

itoggle caption Stephane de Sakutin/AFP/Getty Images

In 1990, Nelson Mandela (wearing a dark suit, pointing down) visited the graves of family members in Qunu, South Africa. A grandson's 2011 decision to move some relatives' remains to another site was followed by a lawsuit and court action. Juda Ngenya /Reuters /Landov hide caption

itoggle caption Juda Ngenya /Reuters /Landov

Near the end of his 27 years in prison, Nelson Mandela was taken to secret meetings with government officials and for drives around Cape Town. Here, he returned to his Robben Island prison cell for a visit in 1994, shortly before he became South Africa's first black president. Louise Gubb/Corbis hide caption

itoggle caption Louise Gubb/Corbis

A Meeting Of Great Minds: During his 1966 visit to South Africa, Sen. Robert F. Kennedy met with anti-apartheid activist Chief Luthuli and later spoke publicly about their meeting. Because of a government ban on media coverage of Luthuli, it was the first news many had of their leader in more than five years. Shoreline Productions hide caption

itoggle caption Shoreline Productions