Situated in the Woonderboom Nature Reserve, this ruin is one out of the three forts built by German architects at the turn of 20th century.
Wikipedia http://en.wikipedia.org/wiki/Fort_Wonderboompoort#Fort_Wonderboompoort
Address (Unnamed Road), Pretoria 0182, South Africa
Coordinates -25°41'32.313" N 28°11'39.297" E