Silver and gold

I thought this was such a beautiful sight, looking down into the thermal water at Mammoth Hot Springs, Yellowstone National Park, Wyoming, US. It was taken somewhere near Canary Spring, on 12 September 2012, the second day of a week's holiday with friends from England.

"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