Hundreds of black youths died at the hands of police during protests against the enforced use of Afrikaans in schools that began on June 16, 1976, in the Johannesburg township of Soweto.
The protests were a turning point in the anti-apartheid struggle, and the brutal police response set international public opinion against the white regime.
On Friday, Thabo Mbeki, the president, accompanied by dignitaries which included Nelson Mandela's former wife, Winnie, led a march of hundreds from Soweto's Morris Isaacson School - one of the key points of the 1976 uprising - to a memorial to arguably its most famous victim.
They stopped briefly to observe a minute's silence to honour the memory of Hector Pieterson and the hundreds of other people killed by police over the next year.
"This day ... is a moment of thanksgiving dedicated to the young people of our country for the contribution they made to free South Africa from the tyranny of apartheid," Mbeki later told a crowd of more than 50,000 gathered for the commemoration at a giant football stadium outside Soweto.
Mbeki and others laid wreaths at Pieterson's memorial in Soweto.
Pieterson was among about two dozen black high school students killed by white security forces on that day, during a march by thousands of teenagers and children in Soweto.
Initially, the protest was directed at the white government's insistence that students be taught in Afrikaans, spoken by the mostly Dutch-descended ruling Afrikaners and seen then as the language of the oppressor.
A photo of a dead student came
to symbolise apartheid's brutality
Police opened fire on the demonstrators, killing Pieterson and the others and setting off a wave of national street marches and demonstrations that received worldwide attention and increased black opposition to apartheid.
A photo, showing Pieterson dead in the arms of a strapping young man and Pieterson's sister by his side, went around the world and came to symbolise the brutality of apartheid.
An estimated 500 to 600 young protesters are believed to have been killed by security forces in Soweto alone during the ensuing six to seven months of protests.
The anniversary is marked every year with a national holiday, known as Youth Day.
The 30th anniversary of the uprising is being celebrated against a debate set off by Archbishop Desmond Tutu's remarks in late April that South African whites had not shown enough gratitude for the magnanimity shown by blacks.
His comments drew a strong response from both sides of the racial divide.
Nkosinathi Biko, the executive director of the Steve Biko Foundation which runs programmes to develop youth leadership and son of anti-apartheid activist Steve Biko, said white South Africans should take responsibility for the crimes of apartheid.
"White South Africans must reckon with history for what it is and not for what they wish it to have been," Biko wrote in a newspaper commentary.
Tutu said whites had not shown
enough gratitude to blacks
Biko, who was six years old when his father died in detention in 1977 after being tortured by security police, told AFP that the new generation of black South Africans might not be as gracious as their contemporaries.
"If Bishop Tutu, who is the embodiment of reconciliation, is making these kinds of statements, should we not be concerned that there may be a growing intolerance?" said Biko.
"We hear a lot of community voices that say 'we are well beyond the honeymoon period'," he said.
The debate over whether South African whites should should atone for the sins of apartheid is a recurring one in South Africa, which has won praise for its peaceful transition to black majority rule since 1994.
Carl Niehaus, who served as South Africa's ambassador to the Netherlands and who failed in 2000 to get some South African whites sign a statement apologising for apartheid, said they had failed to recognise that they were the "benefactors of apartheid" and "continue to benefit to this day".
"The 30th anniversary is an opportunity to go back to the white community and say: 'A large number of young people were shot and killed for no other reason than for the fact that they did not want to live in a society where they were second-class citizens'"
Carl Niehaus, MP and ambassador to the Netherlands
"We don't deal with it properly," said Niehaus.
"We seem to want to forget too quickly the damages of apartheid that have been inflicted."
"The 30th anniversary is an opportunity to go back to the white community and say: 'A large number of young people were shot and killed for no other reason than for the fact that they did not want to live in a society where they were second-class citizens,'" Niehaus said.
Both Niehaus and Biko point to the urgency of overcoming poverty in South Africa, still widespread more than a decade after the ANC swept to power.
Many South African whites maintain that they did not take part or condone repression of blacks and that they are being made scapegoats for the ANC government's shortcomings in its drive to combat poverty.
The man who shared a Nobel Peace prize with Nelson Mandela, former president Frederik de Klerk, said that while apartheid was "morally indefensible", South African whites had made sacrifices that deserved recognition.
"It required considerable courage ... to overcome their reasonable fears and put their trust in their erstwhile enemies," De Klerk wrote in his newspaper rebuttal.