This is Green Lake in Tragoess – Austria. The lake is surrounded by the Hochschwab mountains and forests. The name “Green Lake” originated because of its emerald-green water.
During winter, the lake is only 1–2 meter deep and the surrounding area is used as a county park. However, from May to the end of July, when the temperature rises and snow melts, the basin of land below the mountains fills with water. The lake reaches its maximum depth of around 12 m from mid-May to June and is claimed to look the most beautiful at this time. By end of the July, water begins to recede.