There is a place in Austria that is a dry park in the Winter, and a 10m deep crystal clear lake in the summer.
In the summer, no one can find the Grüner See park located near the village of Tragöes because it only appears in the winter.
Grüner See (Blue Lake) is a unique park and lake in the state of Styria, near the village of Tragöess, located at the foot of the Hochschwab mountain range, Austria. From July to the end of the year, this place is known as the largest park in the area with picturesque natural scenery. Locals and tourists enjoy walking, resting on benches or climbing mountains. Located in the heart of the park is a small lake, with a depth of about 1.2 m.
In winter, the park stands out with its mysterious snow-capped mountains. However, when the warm sunshine begins to appear, the snowy mountains melt, turning this place into a lake. 
This place was originally a park with benches, trees, walking paths and trails for visitors to walk. In winter, you can stroll in the park under shady trees.
Because of this strange phenomenon, this destination gradually attracts adventurous tourists. Tourists coming here in the summer can go underwater to explore the interesting ecosystem with protective equipment such as swimming fins and diving mask. For photographers, underwater photography is an experience not to be missed here.
To participate in water sports, you must be accompanied by a professional diver. Hotels around the shore offer diving equipment rental services. However, because of concerns about environmental pollution causing loss of natural beauty, water activities were once banned here.
The divers were not satisfied with this decision and asked the authorities to allow diving to make the park a popular tourist destination in Austria for water sports lovers.
If you are planning to scuba dive, May-June is the best time to come here, swim and look for bushes and underwater gravel paths. In addition, visitors can also explore the interesting lives of benign creatures such as small snails, crabs, insects…
