Diana's Punchbowl

Diana's Punchbowl, also called the Devil's Cauldron, is a geothermal feature located on a small fault in Nye County. The spring is exposed through a cup-shaped depression about 50 feet in diameter at the top of a domelike hill of travertine about 600 feet in diameter. Hot water in the pool of the bowl is about 30 feet below the rim.
-from Wikipedia