An eclectic mix of world leaders including President Barack Obama and Cuban President Raul Castro will eulogize Nelson Mandela before a crowd of nearly 100,000 mourners at a massive memorial service today in the World Cup soccer stadium where the anti-apartheid champion made his last public appearance.

“What a fantastic gift God gave to us in this Mandela, who quickly became an icon, a global icon of forgiveness, of generosity of spirit,” Archbishop Desmond Tutu told a gathering Monday at the Nelson Mandela Centre of Memory.

“He really was like a magician with a magic wand, turning us into this glorious, multi-colored, rainbow people.”

Nearly 100 world leaders and tens of thousands of South Africans of all races and backgrounds were expected to pay their respects to the man who bridged this nation’s black-white divide at the FNB stadium in Soweto — a locale heavy in symbolism as the black township that was at the center of the violent struggle against apartheid.

The 95,000-capacity soccer venue was also the spot where Mandela made his last public appearance at the closing ceremony of the 2010 World Cup. His body will then lie in state for three days at the Union Buildings in Pretoria — once the seat of white power — before burial Sunday in his rural childhood village of Qunu in Eastern Cape Province.

South African authorities rushed Monday to deal with the complex security, logistical and protocol challenges of hosting what promised to be one of the largest and most prominent gatherings of world dignitaries in generations. Besides Obama and first lady Michelle Obama, former presidents George W. Bush, Bill Clinton and Jimmy Carter were to attend today’s memorial, along with Laura Bush and former Secretary of State Hillary Rodham Clinton.

At the stadium, workers busily constructed a stage protected by bulletproof glass and police promised “thousands” of officers would secure the stadium. Still, security appeared lax Monday as the owner of a private security company scrambled to hire guards for today’s event, using his car as a mobile office.

George Mathabe, manager of the Sidas security company, said 1,500 guards would be on duty.

“I’m doing this from the bottom of my heart, just to thank Tata,” Mathabe said, using the Xhosa word for father as an endearment for Mandela, who died Thursday at the age of 95.

“My son is coming tomorrow as a visitor too. He’s going to live in a free country. He’s going to be able to do whatever he likes, thanks to Tata.”

Mourners were already camped out Monday to be the first ones inside the Soweto stadium, where roads were to be closed for several square miles today. Authorities expect overflow crowds to watch a live broadcast of the event at nearby stadiums.

Officers will direct traffic, protect mourners and assist the bodyguards of visiting dignitaries, said Lt. Gen. Solomon Makgale, a spokesman for the South African Police Service.

“We will be on hand to make sure people are able to grieve in a safe environment,” Makgale said.

“Whether we have 10 heads of state coming, or 70 or 100, we do have the capacity and plans in place to facilitate their movement,” he said.

Besides Obama and Castro, eulogies were to be delivered by U.N. Secretary-General Ban Ki-moon and Chinese Vice President Li Yuanchao. Other speakers include the presidents of Brazil, Namibia and India, as well as tributes from Mandela’s grandchildren. South African President Jacob Zuma is to give the keynote address.