A salute in defiance behind bars by eight men, including anti-apartheid leader Nelson Mandela, as they brought to jail after being sentenced to life imprisonment in the June 1964 Rivonia trial, accused of conspiracy, sabotage and treason. (AFP)

African National Congress (ANC) supporters pray in front of the courthouse of Johannesburg, 28 December 1956, to support 152 anti-apartheid militants, among them ANC member Nelson Mandela, during their trial. (AFP)

Nelson Mandela and his then-wife Winnie raising their fists in salute to the cheering crowd who turned up to greet Mandela on his release from the Victor Verster prison near Paarl on 11 February 1990. (AFP/Alexander Joe)

Jubilant crowds mob the car ferrying anti-apartheid leader and African National Congress (ANC) member Nelson Mandela upon his release from Victor Verster prison on 11 February 1990. (AFP/Alexander Joe)

Hours after his release from jail on 11 February 1990, anti-apartheid hero Nelson Mandela in  his first public speech in Cape Town, urged white South Africans to work for a new South Africa. (AFP/Walter Dhaldhla)

A jubilant Sowetan holds up a newspaper announcing the release of anti-apartheid leader and African National Congress member Nelson Mandela on 11 February 1990. Mandela served 27 years in prison. (AFP/Trevor Samson)

South Africans ignoring apartheid laws joined hands in dancing and singing at a mass African National Congress (ANC) rally in Soweto on 11 February 1990 which was originally called to celebrate the unbanning of the ANC but became a celebration for the release of Nelson Mandela. (AFP/Trevor Samson)

African National Congress (ANC) leader Nelson Mandela gives his first TV interview at his home in Soweto on 14 February 1990 after being freed from life imprisonment. (AFP/Alexander Joe)

General view of Orlando stadium in Soweto, on 13 February 1990, where thousands of African National Congress (ANC) supporters turned up to greet Nelson Mandela two days after he was freed from jail. (AFP/Trevor Samson)

In his role of anti-apartheid leader and African National Congress (ANC) member in 1990, Nelson Mandela delivers a speech at Soweto Soccer City stadium, during a rally attended by over 100,000 people to celebrate Mandela's release from jail on 11 February 1990. (AFP/Walter Dhaldhla)

An ambulance carrying former South African president Nelson Mandela arrives at his home in Johannesburg on September 1, 2013 after he was discharged from hospital where he has been treated since June 8 for a recurring respiratory illnes. (AFP / ALEXANDER JOE)

A statue of former South African President Nelson Mandela outside Drakenstein Prison, where he ended his 27 years of imprisonment and walked out a free man in 1990(AFP/Rodger Bosch)

Nelson Mandela (AFP/Barbara Kinney)

US Secretary of State Hillary Clinton was among the last few visitors Nelson Mandela had, when ill health kept him at home in South Africa. They met on August 6, 2012.(POOL/AFP/File - Jacquelyn Martin)

Former South African President Nelson Mandela celebrates his 94th birthday with his great grandchild Zesilo Hlongwane at his home in Qunu, South Africa, July 18, 2012 (AP Photo/Peter Morey Photographic)

Former South African President Nelson Mandela poses with US First Lady Michelle Obama and her daughters Malia (L) and Sasha at his home in Johannesburg in 2011, during Obama's first full day of a six-day visit to southern Africa. (AFP/Nelson Mandela Foundation/Debbie Yazbek)

A handout photo provided on May 16, 2011 by the South African government shows former president Nelson Mandela and his wife Graca Machel in Johannesburg. Machel married Mandela  on his 80th birthday in 1998 (AFP/Elmond Jiyane)

Former South African president Nelson Mandela seen at Sandton on June 17, 2010, battled health issues off and on, becoming more frail in 2013 with a recurring lung infection (AFP/Alexander Joe)

Former South African president Nelson Mandela. (AFP)

Former South African president Nelson Mandela (L) and his wife Graca Machel greet fans before the 2010 World Cup football final between the Netherlands and Spain on 11 July 2010 at Soccer City stadium in Soweto, suburban Johannesburg. (AFP/Thomas Coex)

Former South African president and Nobel peace prize laureate Nelson pictured in 2008. Mandela(AFP/File/Gianluigi Guercia)

Nelson Mandela gets a kiss from one of his grandchildren in Pretoria in 2008 when turned 94. He celebrated his birthday with 12 million schoolchildren who sang a special birthday song for Mandela who asked the world to honour his legacy by performing community service. (AFP/File - Gianluigi Guercia)

Former South African president Nelson Mandela, in London, on June 26, 2008. Mandela went on life support after falling critically ill in June for a recurrent lung infection (AFP/Shaun Curry)

Former South African President Nelson Mandela squares-up with three-time world heavyweight champion Evander Holyfield at Mandela residence in Johannesburg on 7 July 1997. (AFP/Walter Dhaldhla)

Former South African President Nelson Mandela and Queen Elizabeth make a sweep through Pall Mall to Buckingham Palace on 9 July 1996 in London during Mandela' state visit to Great Britain. (AFP/Jean-Loup Gautreau)

Desmond Tutu (right) who was a champion for the anti-apartheid movement and Nelson Mandela while he was in jail, greet each other at St George's Cathedral in Cape Town in June 1996.( AFP)

Former South African President Nelson Mandela paints the face of a young guest at a party held in honour of his 79th birthday in Cape Town. Over 1000 children from all over South Africa, many of them terminally ill, attended the occasion. (AFP/Anna Zieminski)

Former South African President Nelson Mandela visits his former cell in notorious Robben Island prison off the coast of Cape Town where he spent 19 of his 27 years in jail. (AFP/Guy Tillim)

Zinzi Mandela, wearing Xhosa traditional outfit, steps out on her wedding day with her father, former South African President Nelson Mandela, on 26 October 1992  (AFP/Walter Dhaldhla)

Nelson Mandela blowing out candles on his 72nd birthday cake on 18 July 1990, the first such celebration as a free man since 1960. The party in his Soweto home included his then-wife Winnie (in pink-white headgear), family and friends . (AFP/Walter Dhaldhla)