5. Grand Prismatic Spring: A Giant Blue Eye With a Rainbow Around It
Location: Wyoming, United States
Viewed from above, this Yellowstone hot spring resembles an enormous eye staring out of the ground. A deep blue center gives way to colored bands, with orange fingers spreading into the surrounding landscape. It looks like an artist spilled several buckets of pigment into one perfectly chosen spot.
Much of the color around the edges comes from communities of heat-loving microorganisms. Different conditions support different organisms and pigments. The deep, clear water in the center produces its blue appearance through the way it interacts with sunlight.
That makes the scene more interesting than a simple mineral stain. Part of the rainbow is alive. The full pattern is easiest to understand from an elevated view, while steam and changing light can obscure sections at ground level. And despite its swimming-pool colors, this is a dangerous thermal feature. The boardwalks and designated viewpoints are where this particular illusion should be enjoyed.
