During the fall and winter, you can hike along the trails of Austria's Grüner See (or Green Lake) park. But as spring comes on, the snows melt down from the surrounding mountains, turning the area into a beautiful lake where scuba divers can see what above-ground scenes look like underwater.
By June, the lake's waters, fed by the snowy Hochschwab Mountains, can get up to 30 meters deep, completely submerging the benches, wooden walkways, and railings that aid travelers during the cooler months. It makes for some curious sights, including fish swimming along hiking trails, and grasses waving beneath the water. Fortunately, the local flora and fauna seem well adapted to the yearly growing and shrinking of the lake.
The Daily Mail and the LA Times both have photographs of Green Lake, including some stunning underwater images. The video above, by Alexander Benedik, offers a brief and relaxing tour of these unusual waters.