The huge Yellowstone Lake covers only a small part of the much bigger caldera of the super volcano. Here, Yellowstone's thermal areas also extend into the lake. This pool developed 150.000 years ago after one of the volcanoes explosions. The heat-resistant thermophile bacteria create the colors of the pool. This water is permanently boiling. Only few filamentous bacteria can survive under such hostile conditions.
Pentax K2, Pentax 28mm, f/22, 1/15sec, Kodak E6, ISO 100, polarization filter, tripod