Vrelo Bune

At the eastern end of Blagaj, this site (Vrelo Bune) is magnificent: waterfalls, a footbridge, old mills, the famous tekké and the Green Cave from which pure, cold, tumultuous water emerges, at the foot of the steep 200 m-high cliff of the Orlovača hill. When the current isn't too strong, it's possible to dinghy into the first part of the 10 m-deep Green Cave (Zelena Pećina). It was used as a shelter by Neolithic man. It owes its name to the aquatic vegetation reflected on the walls. The second part of the cave, on the other hand, is dark and dangerous: the spring gushes forcefully from the depths of the earth. In reality, it's not a "spring", but an exsurgence. The waters of the Buna come from an underground network in the karstic massif of Mount Velež. It is one of the largest karst exsurgences in Europe, with an estimated flow rate of 43,000 liters per second. The network was first explored by French divers in 1996. In the course of various campaigns, they ascended 400 m to depths of between 65 and 90 m, with strong currents and poor visibility. It was in these conditions that a French diver died here in 2008. Much less frightening at the surface, the Buna then meanders for 9 km through Blagaj and on to the village of Buna, where it joins the Neretva in a very surprising way at the "Buna canals".