This is beautiful (and a bit creepy, if you’re uneasy around water and submerged things):
Grüner See, literally “Green Lake”, is a lake in Styria, Austria, near the town of Tragoss,located at the foot of the snow-capped Hochschwab mountains. During winter, the lake is only 1-2 meter[s] deep and the surrounding area is used as a county park. It is a particularfavourite site for hikers. But as the temperature starts rising in spring, the ice and snow on the mountaintops begins to melt and runs down into the basin of land below. The lake swells up to engulf the entire area including the park. During summer, the lake reaches its maximum depth of around 12 meter and is claimed to look the most beautiful at this time.
Apparently, the lake is popular among divers when it’s at its summertime deepest. Check out more stunning images of Grüner See here.