forest in western Belarus and eastern Poland. It is one of the largest surviving areas of primeval mixed forest (pine, beech, oak, alder, and spruce) in Europe and occupies more than 460 square miles (1,200 square km). The Belovezhskaya Forest is located in Brest and Hrodna (Grodno) oblasti (provinces) of Belarus and in Podlaskie województwo (province) of eastern Poland near the headwaters of the Narev (Polish: Narew (Narew River)) and Lesnaya (Leśna) rivers, tributaries of the Bug (Bug River). The forest has a wide range of flora (some conifers and hardwoods have attained ages of 350 to 600 or more years, heights in excess of 150 feet 【45 metres】, and diameters greater than 6 feet 【2 metres】) and fauna (including elk, deer, lynx, and wild boar) from both western and eastern Europe. Hunted into extinction in the wild after World War I, the European bison, or wisent, was reintroduced to the Belovezhskaya with zoo-bred animals. The forest remains the European bison's most notable home, though the animals are now also found again in other parts of Europe, including Lithuania, Russia, and Ukraine. Once the hunting grounds of kings and tsars, the Belovezhskaya is the oldest nature preserve in Europe. Both the Polish and Belarusian portions of the forest have become national parks, and both areas were designated as World Heritage sites (World Heritage site) (the Polish (World Heritage site) portion in 1979 and the Belarusian (World Heritage site) portion in 1992).