What makes it so grand? Firstly, it’s deeper than a 10-Story Buildingwith extremely hot water traveling 121 feet from a crack in the earth then rising surface of the spring. Secondly, it is the third largest spring in the world, the Grand Prismatic is bigger than a football field at 370 feet in diameter.  And lastly, the hot spring has bright bands of orange, yellow, and green ring the deep blue waters in the spring. The multicolored layers get their hues from different species of thermophile (heat-loving) bacteria living in the progressively cooler water around the spring. And the deep blue center is because water scatters the blue wavelengths of light more than others, reflecting blues back to our eyes.