Yellowstone NP

21. Mammoth Hot Springs

At Mammoth Hot Springs, a rarer kind of spring is born when the hot water ascends through the ancient limestone deposits of the area instead of the silica-rich lava flows of the hot springs common elsewhere in the park. The results are strikingly different and unique. They invoke a landscape that resembles a cave turned inside out, with its delicate features exposed for all to see. The flowing waters spill across the surface to sculpt magnificent travertine limestone terraces. As one early visitor described them, "No human architect ever designed such intricate fountains as these. The water trickles over the edges from one to another, blending them together with the effect of a frozen waterfall."