The Vaal Dam is one of the largest dams in South Africa. It is located on the Vaal River near the city of Vereeniging in the province of Gauteng. The dam was constructed in 1938 and has a capacity of almost 17 billion cubic metres. It is a major source of water for the region and supplies water to Johannesburg, Pretoria and other parts of the country. The dam is also a popular recreation spot, with many people visiting it for fishing, swimming and boating.