In the black township of Sharpeville, near Johannesburg, South Africa, Afrikaner police open fire on a group of unarmed black South African demonstrators, killing 69 people and wounding 180 in a hail of submachine-gun fire. The demonstrators were protesting against the South African government’s restriction of nonwhite travel. In the aftermath of the Sharpeville massacre, protests broke out in Cape Town, and more than 10,000 people were arrested before government troops restored order.

The incident convinced anti-apartheid leader Nelson Mandela to abandon his nonviolent stance and organize paramilitary groups to fight South Africa’s system of institutionalized racial discrimination. In 1964, after some minor military action, Mandela was convicted of treason and sentenced to life in prison. He was released after 27 years and in 1994 was elected the first black president of South Africa.

READ MORE: Remembering Nelson Mandela