The hidden Blue Lake of Transylvania: A colour-changing natural wonder

The Blue Lake, a hidden natural wonder in Transylvania, has formed in a crater-like depression and has been attracting increasing global attention in recent decades.

The number of visitors to the lake continues to rise annually. Its origins date back to the 1920s when a mining area collapsed, allowing rainwater and nearby springs to fill the resulting depression. This led to the formation of a lake approximately 45-50 meters in diameter and 4-5 meters deep, as reported by Magyarországom.hu.

Despite its small size, the Blue Lake is one of Europe’s most unique

The Blue Lake is located near Felsőbánya (Baia Sprie) and can be reached on foot via a winding trail, requiring about a 40-45 minute walk. Situated at an altitude of 528 meters, the roughly 3-kilometer path leading to the lake lacks built infrastructure, but the breathtaking view makes the journey worthwhile. According to Máramaros.ro, visitors are urged to respect the environment, as some fail to keep the area clean.

One of Blue Lake’s remarkable features is its colour transformation depending on sunlight and the seasons. In spring, it shines in various shades of blue, in summer it takes on a dark green hue, while in autumn it turns brownish. This phenomenon is attributed to the presence of copper sulfate in the water, which leached from the collapsed mine shafts. The angle of sunlight and wind further enhances this effect, sometimes giving the lake a strikingly intense blue colour.

The Blue Lake was designated a nature reserve over 25 years ago. Local legends suggest that the lake is much deeper than it appears, as it is believed to sit above an ancient mine. Water analyses conducted by authorities have detected sulfuric acid levels of 7.8 milligrams per litre and a pH of 4, indicating that the water poses no health risks and is even safe for swimming.

Surrounded by dense pine forests, the lake’s spectacular natural setting makes it a popular hiking destination for locals in the Máramaros (Maramureș) region. The peaceful and untouched landscape offers a perfect retreat for visitors seeking relaxation in nature.

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