The national park is famous for two reasons. First, it's the home of the European bison, the continent's largest land mammal. Though the bison died out in the wild in 1919, it's been successfully reintroduced here. The park contains several bison breeding reserves, where animals can be viewed living more or less a natural existence.
Second, much of the park shelters what's considered to be Europe's largest swath of original lowland forest, known in Polish as puszcza (primeval forest). It's debatable whether the word 'primeval' can accurately be used to describe this, since there's inevitably been human interaction over the millennia, but much of the park has been undisturbed for centuries, leaving a fascinating mix of old- and new-growth forest, and all of the various flora and fauna that flourish in such a special environment.
The park is divided into three zones: a strictly protected area (Obręb Ochronny Orłówka) of old growth that's accessible only under the supervision of a guide; an area of secondary protection (Obręb Ochronny Hwoźna) that does not require a guide and has abundant hiking and biking paths; and several small bison reserves (Ośrodek Hodowli Żubrów).
The park owes its existence largely to royalty. It was a private hunting ground for the Polish monarchs and later for Russian tsars, and as such was protected for centuries by royal patronage.
These days, Białowieża is a popular weekend destination in summer. People come mainly for the chance to hike, bike and, hopefully, spot a bison (aside from the one on the label of a bottle of Żubr beer).
The starting point for excursions into the national park is the village of Białowieża, 85km southeast of Białystok. It has information points, accommodation, food, and travel agencies that can organise visits to the strictly protected area of the park.
The village straggles along for about 3km on the southern edge of the national park, centred on the rectangular Palace Park (Park Pałacowy). The helpful PTTK office, which can organise guides, and the Hotel Żubrówka are at the southern entrance to Palace Park; the national park's own tourist information centre is near the eastern entrance.
If you're arriving by bus, there are three bus stops in Białowieża: one at the entrance to the village, one just after Hotel Żubrówka (closest to the PTTK office), and one just past the post office (near the eastern gate of Palace Park).