In pictures: Mandela turns 91
Leading figures from the African National Congress, family and friends gathered to help Nelson Mandela celebrate his 91st birthday at his Johannesburg home on Saturday
A steady stream of well-wishers arrived at Mr Mandela's house in Houghton, and Happy Birthday was sung - in English and his native Xhosa tongue
Family members were well represented, and Mr Mandela's former wife Winnie Madikizela also paid a birthday visit
Despite increasing frailty, Mr Mandela got down to the serious business of blowing out candles on his ANC-themed cake - but may have been relieved not to have to deal with a full set of 91
An "inspiration to the world", was the tribute from President Jacob Zuma, who was among those who dropped in for the celebrations
This year South Africa is marking 18 July as Mandela Day - when people are encouraged to do voluntary work in their own communities, for example at this soup kitchen
The Nelson Mandela Foundation hopes Mandela Day will become an annual event and that people around the world will take up the challenge
Later, in New York, artists and musicians, including singer Will.I.Am, Wyclef Jean, Lil' Kim and Gloria Gaynor, performed at Mandela Day: A 46664 Celebration Concert.
Carla Bruni, an international ambassador for HIV/Aids charities, sang in public for the first time since her marriage to French President Nicolas Sarkozy, who was watching the show.
Also on stage were singer Queen Latifah and actor Morgan Freeman, who has been cast to play Mandela in a film biography of his life.