Tschingelhörner

The Tschingelhörner are a chain of mountain peaks in the Glarus Alps, located on the border between the Swiss cantons of Glarus and Grisons. They are composed of several summits on a long ridge, of which the highest is named Grosses Tschingelhorn. The mountain is located between Elm and Flims, west of the Segnas Pass.
East of the main summit is the Martinsloch, a triangular breakthrough, or hole in diameter, through which the sun shines at particular times of the year.
The mountain is part of the Swiss Tectonic Arena Sardona and is a UNESCO World Heritage Site.