There's a Lake in Indonesia that has the same pH value as car battery acid:


The Kawah Ijen Lake is located in a crater. The lake is the largest sulfuric acid lake in the world. The actual pH level in the lake is 0.5! As soon as you put an aluminum can in the acid it begins to sizzle and bubble. Within 20 minutes the material is eaten away to the point of it being as thin as tissue.

Despite the dangerous situation, there are people who actually work here. The crater happens to be a sulfur mine. Miners collect and carry huge loads of pure sulfur up from the crater floor.

The miners receive roughly $10 a day for their work in the hazardous environment. Clouds of sulfur dioxide gas are all over the area, and it's considered one of the most dangerous places in the world to work in.