Boardwalks wind around the otherworldly terraces at Mammoth Hot Springs, leading to emerald and azure pools and vast platforms of white stone. Steaming, mineral-rich water glides over the terraces every day, forming rivulets, pools and miniature falls. At Mammoth Hot Springs, Yellowstone National Park. http://mms.nps.gov/yell/features/mammothtour/index.htm.
