Water for Old Faithful Geyser of California comes from an underground river that is 350°F (177°C) and lies 2 miles below the earth's surface. As it flows over hot molten magma deep in the earth, it boils, expands, and collects in large cavities. Under tremendous pressure from the heat, the water is forced through fissures and fractures and erupts with an outpouring of steam followed by hot dancing water. At the time of eruption, the temperature of the water and steam drops to 122-140°F (50-60°C). In the early days of the National Geographic Society, it was declared one of only three faithful geysers in the world because of its regular eruptions, and it soon became one of the most visited places in the American West. The rainbows that form in its predictable sprays of mist are a notable feature in this serene setting at the top of Napa Valley, and it remains one of the most photographed places in California. Centuries ago, the people of the native Wappo Indian Tribe believed in the Legend of the Healing Waters. They noticed steam rising through the earth and mineral waters bubbling out of the ground, discovered the healing properties of the waters and their restorative effect on tired and aching muscles, and used the mud to treat bee stings and sunburns with great success. Word of the legend spread, and people traveled great distances to experience the benefits of the healing waters, detox in bamboo sweat lodges, soak in the natural pools, and enjoy the serenity of Mount Saint Helena.