Hot springs form when heated water emerges through cracks in the Earth’s surface. Unlike geysers, which have obstructions near the surface (hence their eruptions), water from hot springs flows unobstructed, creating a nonstop cycle of hot water rising, cooling and falling.

In the Grand Prismatic Spring, this constant cycle creates rings of distinct temperatures around the center: very, very hot water bubbles up from the middle and gradually cools as it spreads out across the spring’s massive surface.

Water at the center of the spring can reach temperatures around 189 degrees Fahrenheit which makes it too hot to sustain most life. Because there’s very little living in the center of the pool, the water looks extremely clear, and has a beautiful, deep-blue color.

But as the water spreads out and cools, it creates concentric circles of varying temperatures—like a stacking matryoshka doll, if each doll signified a different temperature. And these distinct temperature rings are key, because each ring creates a very different environment inhabited by different types of bacteria.

And it’s the different types of bacteria that give the spring its prismatic colors.

Via Smithsonian.com.