The Nelson Mandela Memorial Service is taking places at Johannesburg's FNB stadium, which has a capacity of 95,000. NBC News is live streaming the memorial service that is dubbed as the biggest funeral in history.

American President Barack Obama attended the funeral with the US delegation, that comprises former US Presidents George W. Bush, Bill Clinton and Jimmy Carter, along with their families. 

Barack Obama delivered a power-packed speech in honor of Nelson Mandela, the relentless anti-apartheid activist.

Calling Mandela as 'a giant of history', Barack Obama said in his honor, 'Mandela taught us the power of action, but also ideas; the importance of reason and arguments; the need to study not only those you agree with, but those who you don't.'

'It took a man like Madiba to free not just the prisoner, but the gaoler as well,' said Obama, referring to Mandela's fight against race discrimination/apartheid.

President Obama arrived late by an hour, due to heavy traffic on the way to the stadium.  Obama greeted and shook hands with his counterparts from other countries, most notably Fidel Castro's brother and Cuban President Raul Castro and Brazilian President Dilma Rousseff, putting aside the controversy over alleged charges of spying by National Security Agency.

While the crowd cheered for President Obama's speech, they booed and jeered at the South African President Jacob Zuma, forcing Cyril Ramaphosa, the coordinator of the service, to call for discipline.

In his speech, Zuma said, 'Today Madiba is no more. He leaves behind a nation that loves him dearly and a continent proud to call him an African. He leaves behind an entrenched legacy of freedom, human rights and democracy in our country, Zuma says. In his honour we commit ourselves to continue to build a nation made up of these values.'

The Heads of State and political dignitaries from China, Zimbabwe, India, Namibia, France and almost all the countries of the world attend to pay their homage to Nobel Prize Winner Nelson Mandela.