Looks like an edited image at first but it is a real park and a real lake but not at the same time.  This is a  place in Austria that is a dry park in the winter and a 10 meter deep lake in the summer.  Strange right?

How could that be?  It is a natural phenomenon because it is an area located at the foot of the Hochshwab Mountains in the Austrian region of Styria and that location is what makes it a part time park, and part time lake.  Actually what happens is that the ice and snow around the mountains melts during the summer months and actually floods the park at the foot of the mountain.

During the winter months, the park and the mountains are dry and is a good place for hiking especially that it is far from the city.   But during summer months, this park is actually a 10m deep lake and is called the Green Lake.  Maybe because the color of the plants and grass in the park reflects on the lake.  Nevertheless, this lake attracts divers who are curious to see how the park looks like underwater.

(Thanks to Paulskie Lada for showing me this place)