People having a Picnic at Cetina River Spring , also known as Eye Of The Earth, a karst spring at the foothills of Dinara mountains, Croatia

cetina river spring izvor cetine eye of the earth croatia eye of the earth dragons eye blue hole cetina croatia dalmatia omis cold karst spring karst hydrological system aerial birds eye perspective drone view topdown deep turquoise emerald lake pond underground drainage visually impressive hidden gem unique shape natural wonder unknown depth ice bath crystal clear groundwater outflow wellspring natural pool phenomenon protected hydrological monument natural marvel sinkhole picnic croatian landscape nature tourism swimming extraordinary shape underground river crystalclear lagoon people