The Grand Prismatic Spring (also known as the Great Rainbow Hot Spring) is the largest hot spring in the United States and the third largest in the world. It is about 75 to 91 meters wide and 49 meters deep. About 2000 liters per minute will flow out and the temperature will be about 71 °C. The beauty of the large prism hot spring is that the color of the lake changes with the seasons. In spring, the lake changes from green to brilliant orange-red, which is due to the algae and pigment-containing bacteria living in mineral-rich water. Microorganisms, the proportion of chlorophyll and carotenoids in their bodies changes with the seasons, so the water body also shows different colors. In summer, the chlorophyll content is relatively low, appearing orange, red, or yellow. But in the winter, due to lack of light, these microorganisms produce more chlorophyll to inhibit the color of carotenoids, so they see the water body is dark green.