An interfaith service kicked off the day's events in Pretoria, at the Freedom Park building dedicated to the country's liberation heroes.
"Twenty years of democracy has been possible because of Mandela," tribal chief Ron Martin said as the sun rose over the Pretoria hills and the smell of herbs burning in spiralled antelope horns wafted over the ceremony.
Veterans of the anti-apartheid struggle attended a wreath-laying ceremony at the base of a five-metre statue of a smiling Madiba, the clan name by with South Africans affectionally call their nation's favourite son.
"Madiba is, in spirit, the same even today," said Machel. "I know Madiba is smiling, Madiba is happy because he is amongst the family he chose to build."
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Later in the day, bells, hooters, vuvuzelas and sirens will chime, honk, blow and wail for three minutes and seven seconds -- followed by three minutes of silence: a six-minute and seven-second dedication to Mandela's 67 years of public service.
South Africans were also finding their own ways of remembering the former president who led their country out of the dark days of apartheid after enduring 27 years in prison.
For example, tattoo studios in the country have reported an ever-growing demand for Mandela-inspired ink.
Fellow Nobel Peace Prize laureate Archbishop Emeritus Desmond Tutu called on South Africans to emulate Mandela's example in a statement to mark the anniversary.
"Our obligation to Madiba is to continue to build the society he envisaged, to follow his example," Tutu said, referring to Mandela by his clan name.
The iconic leader passed away at the age of 95 last year after a long illness.