In a sign of unity  — “ubuntu” — as president Barack Obama of the U.S. put it — thousands of South Africans, world leaders, other dignitaries and celebrities gathered at the FNB soccer stadium in Johannesburg Tuesday for Nelson Mandela’s memorial service.

Mandela will be buried on Sunday, Dec. 15 in Qunu, his ancestral home in Eastern Cape province.

Crowds endured a heavy downpour that persisted all through the event, with some enthusiastic youth dancing throughout the ceremony.

The reconciliatory mood at the FNB stadium was clearly shown when Obama shook hands with Cuba’s Raul Castro — their countries maintain an ideological enmity lasting more than 50 years, a Reuters report said.

The two countries have in recent years taken some steps toward mending the relationship, raising hopes they could be on the verge of a breakthrough in diplomatic relations.

“There is a word in South Africa – ubuntu – that describes (Mandela’s) greatest gift: his recognition that we are all bound together in ways that can be invisible to the eye; that there is a oneness to humanity; that we achieve ourselves by sharing ourselves with others, and caring for those around us,” Obama said when he took the stage amid wild cheers from the crowd.

Obama said Mandela had fought so that people could stand up with moral dignity and he was not afraid to compromise anything for the sake of a larger goal.

In his speech, Castro said, “Mandela’s life tells us, only the concerted efforts of all nations will empower humanity to handle its challenges.”

The ceremony, which ran two hours late, was opened by African National Congress (ANC) Deputy President Cyril Ramaphosa.

There were mixed reactions as President Jacob Zuma stood to give his speech. Most cheered him but some booed the South African leader.

Discontent against Zuma emerged from several scandals he has been embroiled in before and during his presidency, most recently over his private estate at Nkandla, KwaZulu-Natal.

With a presidential election planned in 2014, it’s a concern and embarrassment to the ruling ANC.

Former president Thabo Mbeki was cheered wildly when he was ushered onto the stage, matched only by the applause for Mandela’s former wife, Winnie Madikizela-Mandela.

Zimbabwean President Robert Mugabe also got a big applause as he entered the stadium.

Other world leaders paid homage to Mandela at the memorial recalling his many accomplishments including U.N. Secretary-General Ban Ki-moon who said the world had lost “one of the greatest leaders of our time.”

The U.S. sent its president and three former presidents to the memorial service. The U.K. and France sent their prime ministers, as did more than 90 countries.

Palestinian Authority President Mahmoud Abbas also attended the ceremony. Israel sent Knesset Speaker Yuli Edelstein.