The Buna river is a short river in Bosnia and Herzegovina and it is a left bank tributary of the Neretva river. Its source (Bosnian: Vrelo Bune), a strong karstic spring, emerging from high karstic cavern beneath a high vertical cliff. This region is specific for the diversity of its above-ground and underground hydrography. The source of the Buna river is the finest example of an underground karst river. It's one of the largest and most beautiful springs in Europe, producing approx. 30 m3/s with extremely cold and clean water. The architectural ensemble of the Blagaj Tekke (a Sufi monastery) stands by the source of the Buna river, not far from the centre of Blagaj. The musafirhana (guest house) and türbe (mausoleum) are tucked into the natural surroundings, constituting a single entity with the cliffs, source of the Buna river and mills. The musafirhana of the Blagaj tekke and the türbe have been preserved to this day. The musafirhana was built before 1664, and rebuilt in 1851 - its original appearance is not known. The building was subsequently repaired on several occasions. The ensemble of the Blagaj Tekke was presumably built very soon after Ottoman rule was established in Herzegovina, around 1520 at the latest. (source: wikipedia)