The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world,[3] after Frying Pan Lake in New Zealand and Boiling Lake. It is located in the Midway Geyser Basin.Fountain Geyser, Yellowstone National ParkGrizzly Bear Sow #399 and three cubs, Grand Teton National Park, Jackson Hole, WyomingA bull moose pauses to cast his reflection onto the reflection of the Grand Tetons in a beaver pond in Grand Teton National ParkBull moose herd in Grand Teton National Park, Jackson Hole, WyomingBull bison, Grand Teton National Park, Jackson Hole,Pronghorn Antelope, Grand TetonsGrizzly Bear, the PreacherMoose-Tower Falls, Yellowstone National Parkbull Elk herdTemperature 172°F Dimensions 30x57 feet. Depth 53 feet. Abyss Pool is a colorful and interesting pool in the West Thumb Geyser Basin. Abyss is the deepest pool known in Yellowstone and received its name for its abyss-like depth. The dark green-colored water gives the illusion of a bottomless pool. Vandalism may have changed this pool's temperature. Coins and other debris thrown in have caused the vent to plug. The reduced spring flow also reduced the pool temperature, allowing abundant algae growth along the edge and run-off channels. The extensive microbial mats now support ephydrid flies, spiders and killdeers. An unusual eruption in 1987 caused the pool to surge and temporarily destroyed the microbial mats.Yellows Bellied Marmot, Yellowstone National ParkTwo Wolves, Gibbon River, Yellowstone National ParkHuge Grizzly Bear, the Preacher, Yellowstone National ParkMoose Calf, Yellowstone National ParkBald Eagle, Jackson Hole, WyomingGrey Yellowstone Wolf resting after a big meal, Lewis River, Yellowstone National ParkOtters, Trout Lake, Yellowstone National ParkPine Marten, fall colors, Caribou/Targhee National Forest, Swan Valley, IdahoGolden Eagle, Swan Valley, IdahoSpring Gulch Bull ElkBeaverGrizzly Bear cub, Grand Teton National ParkBloody antlered moose. This bull moose has just rubbed off the velvet of his antlers, a moose's velvet is full of blood vessels. Grand Teton National ParkA grizzly bear who has become to be known as Blondy who roams Grand Teton National ParkBlack wolf of the Pacific Creek pack that roams Grand Teton National Park.A Black Bear in Yellowstone National ParkBlack Bear, signal mountain, Grand Teton National Park, Jackson Hole, WyomingBison, bulls, fighting, locking horns, metaphor,Bison Crossing Yellowstone RiverSpring time in Yellowstone is when we get to watch the new crop of bison calves proliferate. Colloquially known as "red dogs" they are fun to watch and these temporarily cute little critters hop, run, jump and play across the landscape of Yellowstone National ParkMajestic Bull Elk in Golden Aspens in Jackson Hole WyomingBison, autumn color, Grand Tetons, Jackson Hole, WyomingAmerican Kestrel, Swan Valley, Idaho