Green Lake (Grüner See) in Styria, Austria, is an amazing place. For half of the year, it’s an underwater village with fish swimming through the branches of trees, a floor covered in grass, benches and bridges.
For the other half, it is over ground. In the frozen winter months the area is almost completely dry and is a favorite site for hikers. As the temperature begins to rise in spring, the ice and snow on the mountaintops begins to melt and runs down into the basin of land below. The waters are at their highest in June when it becomes a mecca for divers keen to explore the rare phenomenon.
(Source: sci-universe, via lady-loki-laufeyson)