Members of labour federation Cosatu rolled back the years with a spirited and moving rendition of an undiluted version of the national anthem Nkosi Sikelela i Africa.
The anthem was sung with the vigour of workers of 20 years ago under the leadership of then Cosatu president, Elijah Barayi.
It was during Barayi's leadership that the apartheid regime in its desperate attempt to suppress the federation bombed Cosatu's head office in Johannesburg.
Unionists yesterday gathered in Freedom Park, Pretoria, to commemorate the day, relive some of their experiences and show appreciation for the sacrifices made by workers.
Cosatu president Willie Madisha said that the regime was trying to destroy the spirit of workers.
"The apartheid forces bombed our house because it wanted to undermine the unity of workers; but that act was a blessing in disguise because that brought our people together," he said.
He said that when the history of the struggle is written, the bombing of Cosatu House will form a major chapter.
General secretary Zwelinzima Vavi, who spoke on behalf of Jay Naidoo who was a secretary of the federation then, recalled the biting winter morning.
Reading from Naidoo's prepared speech, Vavi said Cosatu leaders were prevented from entering the building after it was bombed.
In anger, Naidoo told police that after they had "bombed, killed, arrested workers now they are preventing us from entering our building".
The Russian-made bomb was planted after Barayi's stinging address to the late president PW Botha in Kings Park, Durban. With his pointed finger, Barayi gave Botha six months to scrap pass laws, unban political organisations, release Nelson Mandela and to do away with the homeland system.
One of Cosatu's lawyers, Peter Harris, said the country should not forget the sacrifices people and organisations like Cosatu made towards liberation.