Blue Lake (Modro jezero) is 800m long and 400m wide karst chasm. It is situated at the edge of the town of Imotski.  On the south end, the chasm is 150m deep, while it reaches as deep as 290m on its north end. The level of water is changing throughout the year – sometimes it is as deep as 90m, but it is not rare for the lake to completely dry up in early autumn, forming a perfect spot for traditional football match.  In late 19th century, the path (1100m) has been built to make the access to water easier.  Gazing at lakes from several viewpoints and swimming are the favourite pastimes of Imotski citizens and their guests. Red Lake (Crveno jezero)  is just 1.5 km away from Blue Lake, intimidates the visitors with its red steep rocks which are ending in the 300m wide chasm. The lake bottom is below the sea level, while the level of water is above sea level, which makes this lake a rare example of crypto-depression in Croatia. On its north side, its slopes are 550m high, and the level of water varies throughout the year – however less than in Blue Lake – and on average, the water is 300m deep. By its east edge, there is prehistoric Gradina, around 4000 years old.