Gruner See (Green Lake) is a lake in Styria, Austria known for its shimmering, emerald-green hue and its fluctuating depth throughout the year, at times leaving a park completely submerged in it. The site has proven to be an attraction for divers.
Travel: Austria's Green Lake in the Hochschwab Mountains is a hiking trail in the winter. The snow melts in early summer and creates a completely clear lake. The lake has a grassy bottom, complete with underwater trails, park benches, and bridges.