The thermal features at Midway Geyser Basin may not gurgle and spout but they are brightly colored and colossal. At 370 feet (112.8 m) wide Grand Prismatic Spring is the largest hot water pool in Yellowstone and third largest in the world. Yet what makes this hot spring truly stunning is its ringed perimeter, green, yellow and orange. Excelsior Geyser, a gaping crater 200 x 300 feet, discharges more than 4,000 gallons (151,000 liters) of water each minute. And while Excelsior no longer acts like a geyser its orange and yellow carpet ushers run-off in elegant fashion.