Grand Prismatic Spring, Hot spring in Yellowstone National Park, USA
The Grand Prismatic Spring is the largest hot spring in the United States and the third largest in the world.
It was first described in detail by geologists working in the Hayden Geological Survey of 1871.
The spring's vivid colors inspired its name, which refers to the optical prism that breaks light into its constituent spectral colors.
Visitors can view the spring from a boardwalk or from an overlook on a nearby hill.
Its striking coloration is due to pigmented bacteria in the microbial mats around the edges of the mineral-rich water.
Location: Wyoming
Source: Wikimedia