Do you know why Lake Brienz is turquoise? It is because of tiny particles of sediment washed into the lake by glacial waters from the Lütschine and the Aare. As these extremely fine glacial particles sink very slowly, they produce an extraordinary visual effect that is only enhanced by the cleanliness of the lake.

Lake Brienz in Switzerland is famous for its vibrant, almost surreal turquoise-blue color, which is caused by a scientific phenomenon called "Glacial Flour." Tiny particles of rock are ground down by glaciers in the surrounding Alps into a microscopic silt. These particles are carried into the lake by the Aare and Lütschine rivers and remain suspended in the water rather than sinking. When sunlight hits the lake, these fine mineral particles scatter the shorter wavelengths of light—specifically blues and greens—reflecting them back to your eyes. The color is most intense in the spring and summer when the snowmelt is at its peak and the sun is high. Interestingly, nearby Lake Thun is less vibrant because the sediment often settles out in Lake Brienz first before reaching the next body of water.