(BBC): Tens of thousands of South Africans have joined dozens of world leaders for the national memorial service for former President Nelson Mandela.

The service was held in front of a vociferous crowd in the FNB stadium in Johannesburg, yesterday.
US President Barack Obama said Mr Mandela was a “giant of history”, describing him as the last great liberator of the 20th Century.
The former South African president died last Thursday, aged 95.
The country is observing a series of commemorations leading up to the funeral on Sunday.

‘A MIGHTY LIFE’
The memorial service, which began at about 12:00 (10:00 GMT), lasted about four hours.
It was one of the biggest gatherings of international dignitaries in recent years, with more than 100 current or former heads of state or government attending.
There had been fears people would be turned away. But with heavy rain, security and transport issues, and the fact that Tuesday was not declared a national holiday, areas of the 95,000-capacity stadium remained empty.

Introducing the proceedings, the master of ceremonies, Cyril Ramaphosa, said that Mr Mandela’s “long walk is over… and he can finally rest”.
Current South African President Jacob Zuma made the keynote address but was booed in some parts of the ceremony.
He said Mr Mandela was “one of a kind… a fearless freedom fighter who refused to allow the brutality of the apartheid state to stand in way of the struggle for the liberation of his people”.
Mr Zuma announced he was renaming the Union Buildings in Pretoria, where Mr Mandela will lie in state, as the Mandela Amphitheatre.
Earlier Mr Obama delivered to huge cheers. He said: “It is hard to eulogise any man… how much harder to do so for a giant of history, who moved a nation towards justice.”
He said Nelson Mandela had taught the world the power of action and the power of ideas, and that it had taken a man like Mr Mandela to free not only the prisoner but also the jailer.
Mr Obama said: “We will never see the likes of Nelson Mandela again. While I will always fall short of Madiba (Mr Mandela’s clan name), he makes me want to be a better man.”
On his way to the podium, President Obama shook hands with Cuban President Raul Castro, an unprecedented gesture between the leaders of two nations that have been at loggerheads for more than half a century.
A White House official later said the two had not planned to meet.
“This wasn’t a pre-planned encounter,” the official said, quoted by AFP news agency.
“Above all else, today is about honouring Nelson Mandela, and that was the president’s singular focus at the memorial service. We appreciate that people from all over the world are participating in this ceremony.”
In his address, Mr Castro paid tribute to Mr Mandela as the “ultimate symbol of dignity and the revolutionary struggle”.
Under his brother, Fidel, Cuba was a staunch critic of apartheid, and Mr Mandela had expressed gratitude for that support.
In his speech, UN Secretary General Ban Ki-moon said there was “sorrow for a mighty loss and celebration of a mighty life”.
He said: “South Africa has lost a hero, it has lost a father… He was one of our greatest teachers. He taught by example. He sacrificed so much and was willing to give up all he had for freedom and democracy.”
The first speaker, friend and fellow Robben Island inmate Andrew Mlangeni, said Mr Mandela had “created hope when there was none”.
Many people stood in the rain waiting for several hours to get into the stadium, the BBC’s Pumza Fihlani reports from the scene.
She says the crowds were in high spirits – singing and dancing, stomping their feet – and the stadium had the feel of a political rally.