A changing of the seasons usually means that colors turn, precipitation takes new form, and temperatures rise or fall. When it comes to Grüner See in Austria, the difference is more like 30 feet of water.
At the foothills of the snow-peaked Hochschwab mountains in an Austrian village called Tragöß, Grüner See (meaning “Green Lake”) spends most of the year with a depth of less than 10 feet. A park containing benches, foot bridges, and paths surrounds it. But when spring arrives, snowmelt from the neighboring mountains starts to fill the basin. Walking paths frequented by hikers disappear, benches become submerged, and the lake expands to around 43,055 square feet. With clean, clear water almost 40 feet deep, the lake takes on a new identity and transforms into a destination for scuba divers who are willing to brave the icy waters.
The emerald green color of the lake is a result of those crystal-clear waters and the nearby foliage. It’s a short-lived phenomenon, as the waters start to recede in July.
Unfortunately, the local tourism office is closing Grüner See to divers starting in January 2016 in order to preserve it, but you can take in the sight of this underwater sensation via the videos below (and tons of others on YouTube, if you’re interested).