"The natural muds of Calistoga are famous for their curative, beautifying properties. The land’s original residents, the Wappo tribe, settled in Calistoga some 8,000 years ago. The Wappo believed the geysers’ steaming mineral water had healing powers. Calistoga baths are particularly coveted since they combine two cherished ingredients: natural hot springs water rich with minerals, and volcanic ash that’s abundant in the area’s soil from the eruption of Mount St. Helena millions of years ago. Mixed together, they become an elixir." ~ Visit Calistoga