No, it’s not a Photoshop job. It’s Green Lake (Grüner See), in Tragöss, Austria. Photographer Marc Henauer writes:
In spring, snowmelt raises the lake level about 10 meters. This phenomenon, which lasts only a few weeks, covers the hiking trails, meadows, and trees. The result is magical-to-watch diving landscapes.
(Click the image to inundate.)