South Africa was a nation in southern Africa.
In the unaltered timeline in which WOTAN briefly conquered Earth, the apartheid government collapsed and South Africa became a united, multicultural nation by the end of the 1960s. It made a deal with the Cybermen to augment its weaponry and waged war in Europe to liberate the continent, finally taking the United Kingdom in 2006. (PROSE: The Time Travellers)
During The Year That Never Was, one of the Toclafane was struck down by lightning in South Africa, deactivating it by chance. Martha Jones, Thomas Milligan, and Alison Docherty replicated those conditions to bring down a Toclafane. They soon realised the Toclafane were humans from the end of the universe, who had shared memories. This was suggested by by the one brought down quoting young Creet on Malcassairo. (TV: Last of the Time Lords)