By Holly Yan
More than 90 heads of state are on their way to South Africa for what is expected to be the largest gathering of world leaders in Africa's history.
It's a clear sign of what kind of impact Nelson Mandela left on the world.
Mandela, the activist who spent 27 years in prison before becoming his country's first black president, died Thursday at the age of 95.
U.S. President Barack Obama heads to Johannesburg on Monday for Mandela's official memorial service, which will take place Tuesday in the city's soccer stadium. But the 90,000 seats probably won't be enough to house the many mourners wanting to pay thanks to the great anti-apartheid leader.
A state funeral will be held Sunday in Mandela's ancestral hometown of Qunu in the Eastern Cape province.
At least 91 heads of state and 10 former heads of state have said they're coming to South Africa this week, government international relations spokesman Clayson Monyela said.
In addition to Obama, former presidents Jimmy Carter, George W. Bush and President Bill Clinton will attend. More than two dozen U.S. lawmakers are also scheduled to attend.
Other guests include the Prince of Wales, British Prime Minister David Cameron and U.N. Secretary-General Ban Ki-moon, as well as celebrities such as Bono, Oprah Winfrey and Naomi Campbell.
Out of the public eye, friends who had not seen each other in years have been coming together with Mandela's family in his home, said Zelda la Grange, Mandela's longtime personal assistant.
Mandela called La Grange his "rock" even though she seemed an unlikely confidante. She was a white Afrikaner and an employee of the former apartheid government.
In her first interview since Mandela's death, she described the mood in his home to CNN's Robyn Curnow on Monday.
"Obviously there's sadness in the house," she said, but also, "People are celebrating Madiba's life. They are grateful."
South African President Jacob Zuma, who announced Mandela's death Thursday, referred to Mandela by his well-known clan name Sunday as he asked churchgoers to remember the former president's values.
"When I say we pray for the nation, (it) is that we should pray for us not to forget some of the values that Madiba stood for, that he fought for, that he sacrificed his life for," he said. "He stood for freedom. He fought against those who oppressed others. He wanted everyone to be free."
In a suburb of Pretoria, parishioners said they were grateful for the man who saved them from revenge.
"His presence in our lives meant so much for the Afrikaaner people, allowed them to get rid of their guilt feelings and to participate in the journey that he invited us to join," Wilhelm Jordaan said.
Once again, Mandela has brought the country together.
CNN's Chris Cuomo, Kim Norgaard, Robin Curnow, Arwa Damon and David McKenzie contributed to this report
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