Colors of the Grand Prismatic Spring, Yellowstone NP
The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world.
It measures approximately 370 feet in size and around 121 feet deep (higher than a 10-story building). But its rainbow waters are what really make it fascinating: While the center of the pool's cerulean hue is pretty characteristic, the deep reds and greens, bright yellows and fiery oranges encircling the edges are not. These colors are caused by thermophilic bacteria that thrive on the rich minerals produced by the water around the hot spring. The center looks blue but actually isn't – the blue wavelengths of light are scattered so we see blue when we gaze upon the spring.
