13 April 1985
Eighty thousand Blacks attended a mass funeral in KwaNobuhle township for the twenty-eight people killed by police during a demonstration in Langa on 21 March 1985. The demonstrators were observing the 25th anniversary of the Sharpeville massacre of 21 March 1960. The incident happened when marchers gathered in Langa, a township on the outskirts of Uitenhage in the Eastern Cape, preparing to move on to Kwanobuhle, 10 km away, where the commemorative service for the 1960 massacre was to be held. Unbeknown to the Langa demonstrators, however, the government had banned the event. Police opened fire on the crowd, killing between 20 and 43 people (sources vary). On 13 April 1985 the crowd of mourners packed KwaNobuhle stadium, the intended destination of the marchers on 21 March. Members of African National Congress (ANC)-aligned United Democratic Front (UDF) refused entry to members of competing organisations, notably the National Forum and the Azanian Peoples' Organization (AZAPO). Such tensions would become a recurrent theme. Though there were small-scale conflicts between the mourning masses and the heavy police presence, it was clear that no one was prepared for a large-scale confrontation, and participants in potential crises situations were usually able to defuse tensions before they escalated. The Langa township at Uitenhage is not to be confused with the township with the same name in Cape Town, which is known for the anti-pass march held there on 21 March 1960, the same day on which the Sharpeville massacre took place.
References

Evans B.A., This Day in African History: 13 April, from the African History, [online], Available at: africanhistory.about.com [Accessed: 11 April 2014]