They gathered in the tens of thousands—presidents, prime ministers, royals, celebrities and ordinary South Africans—all united to say farewell to a man hailed as a global symbol of reconciliation.

In what has been billed as one of the largest gatherings of global leaders in recent history, representatives from around the world joined street sweepers, actors and religious figures to pay tribute to Nelson Mandela.

From President Barack Obama to Cuba’s Raul Castro, praise came from all sides in a four-hour memorial service at Johannesburg FNB stadium for the revered statesman, who died Thursday at age 95.

“We will never see the likes of Nelson Mandela again,” Obama said in a speech to roaring cheers.

“To the people of South Africa—people of every race and every walk of life—the world thanks you for sharing Nelson Mandela with us,” he said, calling him a “giant of history.”

Gray skies and pouring rain throughout the service did little to dampen the mood.

Inside the stadium, the atmosphere was celebratory, with people dancing, blowing vuvuzela plastic horns and singing songs from the anti-apartheid struggle.

Around them, huge poster pictures of Mandela hung inside the stadium. In that same place 23 years earlier, Mandela had delivered his first speech after he was released from prison, hailed by supporters as the hope of a new South Africa.

Also known as Soccer City, the stadium was where Mandela made his last public appearance at the World Cup final in July 2010.

On Tuesday, many people carried banners honoring “Madiba,” Mandela’s traditional clan name. Others were draped in materials covered with his face or the green, yellow, black, red and blue colors of the South African flag.

Some had skipped work and lined up for hours to secure seats so that they could pay their respects to a man considered a moral compass and South Africa’s symbol of the struggle against racial oppression.

“There is no one like Madiba. He was one of a kind,” South African President Jacob Zuma said.

“Everyone has had a Mandela moment when this world icon has touched their lives.”

‘Tata Madiba’

The memorial service, coinciding with U.N. Human Rights Day, was the centerpiece of a week of mourning.

It began with a marching band playing the national anthem.

The joyous cries died down as speeches from Mandela’s family and friends, members of the African National Congress, as well as a fellow Robben Island prison inmate, began.

Anguished faces listened quietly as a sorrowful chant to “Tata Madiba” filled the air. “Tata” means “father” in Mandela’s Xhosa tribe.

‘The world has lost a beloved friend and mentor’

Mandela’s gift for uniting foes across political and racial divides was still evident at the service.

Walking up the stairs onto the stage to deliver his speech, Obama shook hands with Castro, an unprecedented gesture between the leaders of two nations that have been at loggerheads for more than half a century.

Obama earlier gave a warm greeting to Brazilian President Dilma Rousseff, kissing her on both cheeks, despite recent tension between the two countries over reports the U.S. government was spying on her communications.

Obama, who like Mandela was his nation’s first Black president, has cited Mandela as his own inspiration for entering politics.

He said his death should prompt self-reflection.

“With honesty, regardless of our station or our circumstance, we must ask: How well have I applied his lessons in my own life?” Obama said.

“It is a question I ask myself, as a man and as a president. We know that like South Africa, the United States had to overcome centuries of racial subjugation. As was true here, it took sacrifice—the sacrifices of countless people, known and unknown—to see the dawn of a new day.”

The presidents of Namibia, India, Cuba and South Africa were also designated speakers, as were Roussef and Chinese Vice President Li Yuanchao.

“South Africa has lost a hero, they have lost a father. The world has lost a beloved friend and mentor,” United Nations Secretary-General Ban Ki-moon said to loud cheers. “Nelson Mandela was more than one of the greatest leaders of our time; he was one of the greatest teachers. And he taught by example.”

The stadium, which can seat around 90,000 people, was not full, and speeches were hard to hear at times. But the celebratory mood was evident as thousands clapped and waved South African flags throughout the service.

CNN’s Michael Pearson, Athena Jones, Holly Yan, Chris Cuomo, Kim Norgaard, Robin Curnow, Arwa Damon Errol Barnett and David McKenzie contributed to this report.