Pilanesberg National Park is a 'Big Five' (Elephant, Rhino, Buffalo, Lion and Leopard) game reserve just over a 2 hour drive from Johannesburg. Situated in a mountainous area, which was formed by an extinct alkaline volcano, of which there are only 3 in the world - Russia, Greenland and South Africa. The volcano was the highest point in Africa 1300 million years ago at about 7KM and has worn down to form 4 concentric rings of mountain with the highest peak being about 700M. This park is the only park where certain species of antelope, namely the springbok and the impala, can be found side by side as the vegetation straddles 2 different biomes i.e. the dry Kalahari and the wetter bushveld of the lowveld, which also allows for a large variety of birds and animals.
The area of the park is about 55000 Hectares and it has about 220Km of road transversing the park with several hides at which one can alight from one's vehicle to view the dam from a discrete vantage point.
Should you have limited time in Johannesburg, a one day tour to Pilanesberg is well worthwhile and if time permits, an overnight stay is a great experience.