Johannesburg - The day apartheid police opened fire on protesting black school children in Soweto on June 16, 1976 will be commemorated in South Africa on Tuesday.Observed as a public holiday, it recalls the day police shot at children marching in Orlando West to protest over Afrikaans as a medium of instruction in the then government's ''Bantu education'' system.Photographer Sam Nzima managed to capture the photograph of 17-year-old Antoinette Sithole running next to Mbuyisa Makhubu carrying Hector Pieterson, who, with Hastings Ndlovu, were among the first to die as police cracked down on any resistance by black people to laws which gave whites rights that other races were denied.In 1996, Sithole testified at the Truth and Reconciliation Commission on events of the day.''When we arrived at Pafeneng there was confusion. There were police. They threw us with tear gas. We ran away and we hid ourselves,'' according to a transcript of her testimony.''There was a gun sound. There was teargas and there was confusion. I saw people hiding themselves and then I hid myself too. While we were standing there I then - I was afraid because I didn't know where Hector has gone to and people were holding something. And then I moved forward and I could not see properly, and I saw Hector's shoe.''They were helped to a clinic by journalists, but Pieterson was already dead.In the days that followed, government buildings were torched, police were stoned, and many black school pupils and political activists abandoned their lives and families in South Africa and left the country to escape the police crackdown, and to build a resistance against apartheid from neighbouring countries.Wednesday's commemorations will include an address by President Jacob Zuma at the Tshwane Events Centre, an Economic Freedom Fighters rally at the University of Limpopo to be addressed by Julius Malema, and a rally addressed by Inkatha Freedom Party president Mangosuthu Buthelezi.Democratic Alliance leader Mmusi Maimane will be at the university in Nelson Mandela Bay for the party's rally.