The Grand Prismatic Hot Spring is the most photographed thermal feature in Yellowstone National Park. 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? That’s because water scatters the blue wavelengths of light more than others, reflecting blues back to our eyes. A challenging and beautiful puzzle. Made in the USA. For ages 9 and up. WARNING: CHOKING HAZARD - Small Parts. Not for children under 3yrs.