The Selous Game Reserve, with an area of about 55,000 sq. km, is the largest well-watered wildlife sanctuary in Africa, and one of the largest protected areas in the world. Its size is simply stunning, bigger than Switzerland, uninhabited and little touched by human interference. It is perhaps the most pristine wilderness still remaining in Africa, with a wide variety of wildlife habitats, including open grasslands, Acacia and miombo woodlands, swamps and riverine forests in the many tributaries of the mighty Rufiji River which flows through the reserve. Due to its unique ecological importance, it was designated a World Heritage Site by the United Nations in 1982. Its wildlife is spectacular, with some of its mammal and reptile populations the largest in Africa, namely buffaloes, elephants, hippos, wild dogs and crocodiles.