So many beautiful patterns and textures are created around the various springs at Mammoth Hot Springs and other hot spring/geyser locations within Yellowstone National Park. This shot was taken from the boardwalk, looking over the railing, near the Main Terrace at Mammoth Hot Springs, on 12 September 2012.

"Mammoth Hot Springs is a large complex of hot springs on a hill of travertine in Yellowstone National Park ... It was created over thousands of years as hot water from the spring cooled and deposited calcium carbonate (over two tons flow into Mammoth each day in a solution). Although these springs lie outside the caldera boundary, their energy has been attributed to the same magmatic system that fuels other Yellowstone geothermal areas... A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption. They are sometimes confused with volcanic craters."

en.wikipedia.org/wiki/Mammoth_Hot_Springs

For a diagram of the Hot Springs layout:

en.wikipedia.org/wiki/File:MammothHotSprings.JPG

Map of Yellowstone National Park:

hfc.nps.gov/carto/PDF/YELLmap2.pdf