The source of the Neretva, the largest and most important Croatian river to flow into the Adriatic, is far from the coast, at a height of 1095 metres. The river is 218 kilometres long, but its journey through Croatia measures only 22 kilometres.
On its longest stretch, it is a typical rapid, with a strong torrential flow eroding the narrow canyon valley. Some thirty kilometres from the estuary to the Adriatic Sea, it changes character, depositing eroded mineral and stone and creating a valley with rivulets and small lakes, through which it slowly meanders. Gradually submerging karst coves, the Neretva built its characteristic landscape among the surrounding hills, creating several relief and morphological wholes. The visually strong karst framework makes for a pleasant counter-point to the plain. The karst phenomena contains interesting subterranean forms, pits and caves. Some fifty caves are known for the richness of their decoration and rare life-forms are found in some of them. For example, the only known underground shell in the world - Congeria Kuscer (Kuscer - a Slovenian shell specialist who discovered it), is a kind of “living fossil” as it moved during its geological history from the surface to underground and adapted itself to a life of permanent darkness. In the same eternal darkness, there lives ‘mans little fish’, a fascinating endemic small creature with fragile legs and a spindly body, the colour of human skin. Occasional storm water can throw it to the surface.
This low-lying delta landscape emanating from the river’s course comprises its most valuable bio-diversity and gave rise to significant agricultural development, while the coastal sedimentary deposits at the very estuary give the coastal area an additional dimension.
