Gauteng offers a vibrant business environment and many tourist attractions, including a rainbow of ecological and cultural diversity. The Vaal Dam covers some 300 square km and is a popular venue for water sport. Numerous resorts line the shore. The Dam also attracts a great diversity of birds. Vanderbijlpark was built during the late 1940s by the Iron and Steel Corporation (ISCOR) to accommodate its employees. Daytime temperatures ranges between 14°C during winter months and 31 °C during summer. The old mining town of Cullinan developed around the Premier Diamond Mine and many of the turn-of-the-century houses still stand. The Mine has produced some of the world's most famous diamonds, including the Cullinan, at 3 106 carats the world's largest. The Willem Prinsloo Agricultural Museum outside Cullinan centres around a farmstead dating from 1880. Traditional farming activities are demonstrated and annual events include a prickly pear festival, mampoer festival and the Agricultural Museum Show. The Sterkfontein Caves near Krugersdorp are the site of the discovery of the skull of the famous Mrs Ples, a 250-million-year-old hominid fossil. The Caves comprise a series of caverns with many stalactites and stalagmites and a huge underground lake. Guided tours are available. The Wonder Cave, about two billion years old, is one of South Africa's most impressive natural assets. In 1999, Sterkfontein and its environs were declared a World Heritage Site. The Krugersdorp Game Reserve provides sanctuary for several game species, including four of the Big Five. The African Fauna and Bird Park houses various species of wildlife and birds. The South African National Railway and Steam Museum at Randfontein Estates Gold-mine outside Krugersdorp houses some of the country's old steam locomotives, a diesel electric locomotive and more than 50 vintage passenger coaches. Train rides are offered once a month. A team of Lippizaner stallions performs regularly at the South African National Horsemanship Centre, Kayalami, near Johannesburg. Visitors to Roodepoort can go on walks and trails through the Kloofendal Nature Reserve, or enjoy a picnic or show at the popular Kloofendal Amphitheatre. The Witwatersrand National Botanical Garden boasts a 70-m high waterfall.
