Sigmund-Thun Gorge, Kaprun, Austria.

In the late Ice Age, about 14.000 years ago, the Kaprun Valley was covered by a powerful glacier. As it flowed slowly down the valley, the glacier carved away the hard limestone, slate and mica cliffs of the Maiskogel and Bürgkogel.

As the glacier melted, it left behind the deep notch, trough which the Kaprun Stream flowed into the valley. 

As much as 32 meters deep and running 320 meters long through the Sigmund-Thun Gorge, the Kaprun Stream has left its mark on the rocky riverbanks, smoothing some rock surfaces and etching whirlpools and deep holes into others.