March 21'st was chosen as it was on this day in 1960 that Sixty-Nine people died in the Sharpeville Massacre in Apartheid South Africa.
Sixty-nine people died on 21 March 1960 when police gunned down unarmed people protesting against apartheid laws.
The dead were honoured as part of Human Rights Day, with church services, the laying of wreaths, and a speech by Deputy President Kgalema Motlanthe.
Critics say people in the township still face poor living conditions.
People gathered at the Roman Catholic church in Sharpeville, and laid wreaths at the cemetery on the graves of those killed in the massacre.
Mr Motlanthe spoke to survivors and relatives of the victims at the Garden of Remembrance.
Later addressing a crowd of about 5,000, he said: "We say never, never and never again will a government arrogate itself powers of torture, arbitrary imprisonment of opponents and the killing of demonstrators."
"In the same breath, we state that our democratic government undertakes to never ignore the plight of the poor, those without shelter, those without means to an education and those suffering from abuse and neglect," he was quoted by the Associated Press as saying.
Defining moment
The Sharpeville Massacre is remembered as one of the bloodiest moments of the liberation struggle, the BBC's Karen Allen reports from Johannesburg.
Fifty years ago, South African police opened fire on demonstrators in Sharpeville township, 50km (30 miles) south of Johannesburg. Sixty-nine people died and at least 180 were injured - many shot in the back as they were trying to flee the scene.
They had gathered outside the police station to protest against pass laws, which required all blacks to carry identity documents - known as pass books - at all times.
No police were ever convicted over the killings.
The Sharpeville massacre led to the banning of the African National Congress (ANC) and its rival liberation movement, the Pan Africanist Congress (PAC), and signalled the start of the underground armed resistance in South Africa.
Today, many in the township are disappointed that the ANC has failed to improve their lives since it came to power, our correspondent says.
Many of the shops in Sharpeville have closed down, unemployment persists and there is a sense among some residents that basic public services are inadequate.
"Our lives started changing with Nelson Mandela's release, but people are still financially struggling and finance is still in white people's hands," Abram Mofokeng told Associated Press news agency.
He was 21 when the massacre took place.
In recent weeks the ANC has faced protests from other communities in South Africa, who fear that cronyism and corruption have overshadowed the party's agenda.
BBC News
