Blue pool of boiling water at Beryl Springs, Yellowstone National Park
Blue pool of boiling water at Beryl Springs, Yellowstone National ParkBeryl Spring's strongly boiling blue pool is about 8 m (25 ft) wide and contains high-chloride liquid water with a near-neutral pH. Immediately behind the pool is a loud, hissing fumarole producing a white cloud of steam. USGS Photo by Pat Shanks, 2002.