Martinsloch
Glarus
Martinsloch is a remarkable natural rock formation located in the Tschingelhörner mountain range of the Swiss Alps, on the border between the cantons of Glarus and Grisons. This triangular hole measures approximately 19 meters wide and 22 meters high and is situated at about 2600 meters above sea level. It was formed through geological faulting processes and offers a unique natural phenomenon: on specific days in March and September, sunlight passes directly through the hole, illuminating the village of Elm below. This event lasts only a few minutes and creates a striking beam of light that can be seen as a spotlight reaching several kilometers. The phenomenon has been recorded historically since at least the 18th century and is associated with the illumination of Elm's church tower. Martinsloch is part of the Swiss Tectonic Arena Sardona, a UNESCO World Heritage Site, highlighting its geological and cultural importance. The site combines natural beauty with scientific interest, attracting visitors who appreciate alpine landscapes and rare solar events.
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Tip: The best times to witness the sunlight passing through Martinsloch are around March 12 or 13 at about 8:52 AM and September 30 or October 1 at about 9:33 AM local time. Visitors should plan accordingly and consider viewing from Elm or nearby vantage points. Due to the short duration and rarity of the event, arriving early is recommended. Protective eye measures similar to those used during solar eclipses are advisable when observing the sun directly through the hole. Advance planning is essential as weather conditions greatly affect visibility. No specific ticket is required as Martinsloch is a natural outdoor site, but checking local visitor information for guided tours or access routes can enhance the experience.
Interesting facts
- •Martinsloch measures about 19 meters wide and 22 meters high, forming a triangular rock window in the mountain ridge.
- •Sunlight shines through Martinsloch only on specific days around March 12-13 and September 30-October 1 each year, illuminating the village of Elm.
- •The light beam created by the sun passing through Martinsloch can be seen as a spotlight reaching approximately 4.7 kilometers, casting a moving light ellipse over the landscape.
- •Historical observers since the 18th century, including Johann Gottfried Ebel and H. Besson, documented the sunlight phenomenon and its effect on Elm's church tower.
- •Martinsloch is part of the Swiss Tectonic Arena Sardona, a UNESCO World Heritage Site, highlighting its geological importance.
History
Martinsloch was formed by geological faulting in the Tschingelhörner mountain range, part of the Glarus Alps.
Historical records from the 18th century describe the sunlight phenomenon illuminating Elm's church tower through the hole.
The event was noted by travelers and naturalists such as Johann Gottfried Ebel and H.
Besson, who observed and documented the solar alignment in March and September.
Over centuries, the phenomenon has remained a celebrated natural spectacle, linking local cultural heritage with alpine geology.
Today, Martinsloch is recognized within the Swiss Tectonic Arena Sardona UNESCO World Heritage Site, preserving its geological significance.