It’s not a natural, but rather a residual lake, appeared in an old copper mine in Butte, Montana, USA. Formed at a depth of 270 meters, the water has an acidity that has not yet been matched on Earth. Heavy metals, extremely hazardous chemicals (arsenic, zinc, cadmium, zinc), not to mention the sulfuric acid, all forming a lethal “soup” for any life form. What is even more serious is that the level of acidity is increasing steadily since 1982.
A sinister incident took place in 1995, when a huge flock of geese landed on the lake’s water. Absolutely all the birds died, the researchers managing to bring out “only” 342 partially dissolved in acid skeletons. After all, the lake is nothing but another “artwork” of man.