Modro Jezero (Blue Lake) is a karst lake located in Imotski, near the border with Bosnia and Herzegovina. It owes its name to its intensely turquoise water color. A narrow path leads above them, with several viewing terraces. The path was created in 1907 thanks to the Austrian Emperor Franz Joseph I who was delighted with the beauty of this place.
The water level in the lake varies depending on the season. The maximum depth is about 220 meters, while the area is 800 x 500 meters. When the water level is deep, swimming competitions are organized here. In summer, the lake often dries up, and its bottom then serves as a football field.
In the walls of the sinkhole there are several caves that were used by local residents as a shelter during World War II. Near the lake there is the ancient fortress of Imotski, whose history dates back to the 10th century. It was around the fortress that the city of Imotski was built.