Buna river is the left tributary of the Neretva River, 9 km long. Its tributary Bunica flows into it in an excursion and campsite Buna. It is very rich with water, one of the strongest sources in Europe.
French divers have explored the underground flow of Buna river, length about 200m. The water is extremely cold and clean and is a habitat for endemic species of brown trout.
The Sports and Tourism Association "Blagaj-City" organizes until September a boat relaxing drive tour by the source of the river in the deep interior of the cave, which costs two euros per person and takes 15 minutes.This is the best anti-stress aspect of tourism, which became a hit in the world.