(CNN) — The calm turquoise waters are a magnet for Instagrammers desperate to take the perfect selfie. But the "Novosibirsk Maldives," as this Siberian lake has been dubbed, is no natural beauty.
It's a highly toxic artificial pond used to dump ash from a nearby coal plant, and, warns the company that runs the plant, unsafe for swimming in.
"In the last week, our ash dump of the Novosibirsk TEZ-5 has become the star of social networks," it said. "But you CANNOT swim in the ash dump. Its water has high alkaline environment. This is due to the fact that calcium salts and other metal oxides are dissolved in it. Skin contact with such water may cause an allergic reaction!"
The company also warned visitors that the bottom of the lake is so muddy that getting out "is almost impossible."
The company went on to warn in capital letters: "THEREFORE, WE ASK YOU VERY MUCH THAT IN YOUR QUEST FOR A SELFIE YOU DON'T FALL DOWN INTO THE ASH DUMP! THIS IS THE BIGGEST RISK."
The water gets its spectacular color from its depth and the various metal oxides dissolved in it, the company said. It is also extremely alkaline, with a pH of more than 8.
Despite the warning, people have continued to flock to the lake in a bid for the most Instagrammable pictures -- from posing on its banks in a bikini to taking to the water on an inflatable unicorn.
"We know that the lake is toxic and didn't enter the water," Marina Zheleznova, a young Siberian woman who staged a photoshoot by the lake with her partner, told CNN. "This didn't stop some Russians to organize whole picnics by the lake. One man even bathed there, which is strictly forbidden."
Another Instagrammer has created a fan account called "Novosibirsk Maldives," which collects selfies taken at the lake.
"I just enjoy photography," Leo Alexey, who set up the page, told CNN. "The place is really interesting although you cannot swim there because of the high content of calcium and metal oxides which may cause allergies."
"I have been there five times, and I plan on going more," he said, adding: "I go there every weekend but I don't touch the water."