The Una River in western Bosnia is one of the clearest rivers in Europe, an extraordinary emerald-green stream that runs through limestone country in a succession of pools, rapids and waterfalls. Štrbački Buk is the most dramatic of these, a broad staircase of cascades where the river drops over a wide barrier of travertine, the mineral deposit built up over thousands of years by the water itself. The roar is audible long before you arrive, and the spray cools the air.
The falls lie within Una National Park, which Bosnia and Herzegovina established in 2008, close to the border with Croatia. The park protects the river, the canyon and the surrounding forest, with trails, viewing platforms and a small visitor centre. You can walk along the river for a few minutes from the car park to a platform just above the main drop, and in the warm months people swim in some of the pools. The water is cold and astonishingly clear, and the colour changes from turquoise to jade with the light.
The Una is also a rafting and canoeing river, and in summer there are organised trips on the calm stretches above and below the falls. An annual regatta of canoes and kayaks attracts paddlers from several countries. The valley has a wild, gentle character, with old watermills, orchards and small farms, and the people are famously hospitable. You may be offered coffee, plum brandy or a plate of grilled meat, and it is polite to accept at least the coffee.
The ride from Bihać is a pleasant country road, winding through villages and low hills, with a surface that is generally acceptable but patchy in places. Traffic is light, and animals, including dogs, cattle and the occasional horse, sometimes wander onto the road. It is worth remembering that this area saw heavy fighting in the war of the 1990s, and warnings about unexploded mines remain in some rural areas. Stay on marked roads and paths and do not wander into overgrown land.
For fuel, Bihać, about twenty-one kilometres away, is the nearest large town and has several stations, banks and supermarkets. Orašac, the nearest village, is smaller. At the falls there is a cafe and a restaurant serving fresh trout, and food is cheap by European standards. Early morning, before the day visitors arrive, is when the light is best and the river seems to belong to you.