The Buna is a short river in Bosnia and Herzegovina; it is a left bank tributary of the Neretva. Its source (Vrelo Bune), a strong karstic spring, is near the village Blagaj, southeast of Mostar. Actually, it is best known by famous Buna Spring (Vrelo Bune), one of the strongest spring in Europe and extremely cold water. The Buna flows west for approximately 9 km, starts at Blagaj and meandering through villages Blagaj, Kosor, Malo Polje, Hodbina and joins the Neretva at Buna village. The Bunica river is main left bank tributary of the Buna.