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.