Modro jezero / Blue Lake
Blue lake in Imotski County .
The Blue Lake is a deep sinkhole formed by the collapse of the roof over a huge underground cave. The cave was formed by water through millions of years, and it collapsed about 5 million years ago. Erosion and earth quakes have formed the sides of the lake so it is now possible to walk on a path all the way down the 220 meter deep sides.
Water depth in the lake varies a lot by season as it is fed by several small streams coming out of caves in the high walls of the lake. In August the lake may completely disappear if there has been no rain fall.