Grand Prismatic Spring, is Yellowstone National Park's largest hot spring. In fact, it's the largest hot spring in the United States and the third largest in the world (New Zealand is home to the largest).

Grand Prismatic Spring displays incredible and contrasting colors. The clear but deep blue of the center of the pool is due to the great purity and depth of the water making the hydroxy blue effect particularly evident.

The rust, yellow and green areas around the spring are the homes of thermophiles -- heat loving organisms.

The spring is about 300 feet in diameter (91m) and 160 feet deep (49m).