Blue Lake is one of the most beautiful natural karst lakes in Croatia located near the town of Imotski. It lies in a deep pit that was probably formed by the collapse of a ventilated underground cave. The total depth from the upper edge is 220 meters and it varies depending on the season. Water levels could reach more than 90 meters in early spring when snow from nearby mountains melts. At the end of the summer, the lake could mystically disappear, so there is a fascinating football field at its bottom. The lake is a popular place for tourists and residents of the town of Imotski because it is very accessible. In addition there are trails that go almost to the bottom of the lake. There are many caves inside the lake, which are very difficult to reach. The best time to visit is winter and spring.