Blue, Blue Sapphire Pool, Biscuit Basin, Yellowstone National Park
Blue wonder at Biscuit Basin thermal area in Yellowstone Park. Fifty years ago you might see geyser eruptions of 150 feet from this crystal clear pool. Now is mostly calm but sometimes in boils and surges with water energy. Its hot up to 200 degrees farenheit. Underneanth the park geologic forces are busy at it sits a a giant volcanic caldera that is active but hasnt bown up for a few hundred thousand years.