Bialowieza is a well-known scientific centre with departments of the Polish Academy of Science, Warsaw University and the Forestry Research Institute which specialise in research on natural forest ecosystems. Numerous research projects are conducted there by scientists from various institutes from Poland and abroad. Walking in the strict protection zone, which is the main site of interest in the Park, is allowed only in groups with licensed guides, along a 4-km walking route which is the only path open to the public there. The protected area Hwozna, merged with the Park in 1996, has two marked walking and cycling routes of 6,5 and 11,5 km. Other attractions are an animal watching tower built in the valley of the Narewka River, the European bison exhibition enclosure and a Natural Museum (presently under reconstruction). The Park has also a Nature Education Centre named after prof. J.J. Karpinski. The Park manages the largest European Bison Breeding Centre and publishes European Bison Pedigree Book, as well as a scientific quarterly National Parks and Nature Reserves and regular updates of the Bibliography of Bialowieza Forest.