From: http://www.nationmaster.com/encyclopedia/Umkhonto-we-Sizwe
Umkhonto we Sizwe logoUmkhonto we Sizwe (MK) (Spear of the Nation)
was the military wing of the African National Congress (ANC).
Founded December 16, 1961, by the ANC and SACP as the answer
to the political, social and economical oppression against blacks
by the South African Apartheid regime. The MK carried out numerous
bombings of military, industrial, civilian and infrastructural
sites. Notable among these is the January 8, 1982 (to coincide
with the 70th anniversary of the formation of the ANC), attack
on the Koeberg nuclear power plant in Cape Town. Umkhonto we
Sizwe was officially disbanded on August 1, 1990.