16th December is known as the Day of Reconciliation, a public holiday in South Africa. This day was intended to create reconciliation and national unity after the end of the apartheid era - in 1994.
The date was chosen as it was significant to both African and Afrikaner cultures.
In the African cultures, 16 December was the anniversary of the 1961 founding of Umkhonto we Sizwe ("Spear of the Nation"), the armed wing of the African National Congress.
For the Afrikaners, this date was commemorated as the Day of the Covenant or Day of the Vow - which was a religious holiday commemorating the Voortrekker victory over the Zulus at the Battle of Blood River in 1838. (wikipedia)