Johannesburg (CNN) -- It’s a moment for the ages.
Tens of thousands of South Africans, dozens of presidents and prime ministers, celebrities and street sweepers all headed to the same place: a stadium in Johannesburg to honor Nelson Mandela at a memorial service on Tuesday.
Despite the rain, crowds clapped, sang and danced as they began arriving at the FNB stadium. Many waved banners honoring the revered statesman or carried his picture.
Dignitaries from around the world arrived in the city to pay tribute, including President Barack Obama, British Prime Minister David Cameron as well as Liberian President Ellen Johnson-Sirleaf. Nobel Peace Prize laureate Archbishop Desmond Tutu and South African President Jacob Zuma were among the first to arrive at the stadium.
The world of entertainment also was well represented with South African actress Charlize Theron and U2’s Bono in attendance.
With 91 heads of state attending, security was tight.
Authorities have been stepping up surveillance as presidents of six nations prepare to pay tribute to the late anti-apartheid leader in a four-hour service that will likely bring much of South Africa to a stop.
Working off plans developed for years in secret, the South African government is using an elite military task force, sniper teams and canine teams to help secure the stadium, CNN’s Arwa Damon reported Monday. In addition, helicopters and military jets frequently fly overhead. “Should anybody, anything dare to disturb or disrupt this period of mourning and finally taking and accompanying the former president to his last resting place, then that person will be dealt with,” Brig. Gen. Xolani Mabanga said Monday. South African officials won’t give details about their security plans—how many police officers, how many troops, precautions to keep the stadium weapons- and explosives-free.
“But we can assure that all necessary steps have been taken, and that is why the leadership of the world and former leaders of the world have confidence to come to our country at this time to share with us this moment,” said Minister in the Presidency Collins Chabane.
The event promises to rival other significant state funerals in recent decades, such as that of former British Prime Minister Winston Churchill in 1965 and the 2008 funeral of Pope John Paul II, which attracted some 2 million people to Rome—among them four kings, five queens, at least 70 presidents and prime ministers and the leaders of 14 other faiths.
At that event, metal detectors and some 15,000 members of security forces stood watch.
Security was also stepped up outside Mandela’s home, where crowds showed up with umbrellas to show their appreciation of a man they said represented unity. Some even said they missed work for the occasion.
“We want to respect our father of the nation, our father of the country. That is why we left work to pay that respect to him,” one South African told CNN.
U.S. officials are satisfied with security arrangements.
“We have not heard any concerns,” Deputy National Security Adviser Ben Rhodes told reporters aboard Air Force One as President Barack Obama flew to South Africa.
“The South Africans hosted the World Cup, so they have experience hosting significant crowds and managing events like this, although clearly this is really a unique event in world history, given the number of leaders coming to pay their respects, as well as the people of South Africa.”
Given Mandela’s ailing health, the U.S. Secret Service made some arrangements in advance, a Secret Service spokesman said. But work that would usually take months to complete has been done in less than a week, the spokesman said.
“It’s a compressed timeline, but there are certain protocols we must have in place for any trip,” the spokesman said.
Those protocols involve securing the president’s motorcade route and hotel rooms and doing security walk-throughs.
The spokesman declined to offer specific details on security measures at the stadium.
While Tuesday’s memorial is the first major event honoring Mandela since his death, it won’t be the last.
A state funeral will be held Sunday in Mandela’s ancestral hometown of Qunu in South Africa’s Eastern Cape province.