Hot springs in the Yellowstone National Park. Photographed here is the Sulphur Caldron, one of the park’s most acidic springs. with a pH of 1.3 (jalmost similar to a batery acid). However there is life in this pool of boiling acid, the thermoacidophiles bacteria have adopted to these harsh conditions. Established in 1872 the Yellowstone is the world's earliest national park, known for its wildlife and geothermal features.