of healing qualities to the water through the numinous presence of its guardian spirit or of a Christian saint, or a ceremony or ritual centred on the well site. Christian legends often recount how the action of a saint caused a spring's water to flow - a familiar theme especially in the hagiography of Celtic saints. Thermal springs The geothermally heated groundwater that flows from thermal springs is greater than human body temperature, usually in the range of 45–50 °C / 110–120 °F, but they can be hotter. Those springs with water cooler than body temperature, but warmer than air temperature are sometimes referred to as warm springs. Bathing and balneotherapy Hot springs or geothermal springs have been used for balneotherapy, bathing and relaxation for thousands of years. Because of the folklore surrounding hot springs and their claimed medical value, some have become tourist destinations and locations of physical rehabilitation centers. Geothermal energy Hot springs have been used as a source of heat for thousands of years. In the 20th century they became a renewable resource of geothermal energy to heat homes and buildings. The city of Beppu, Japan contains 2,217 hot spring well heads that provide the city with hot water. Hot springs have also been used as a source of sustainable energy for greenhouse cultivation and the growing of crops and flowers. Cultural representations Springs have been represented in culture through art, mythology and folklore throughout history. The Fountain of Youth is a mythical spring, which was said to restore youth to anyone who drank from it. It has been claimed that the fountain is located in St. Augustine, Florida, and was discovered by Juan Ponce de León in 1513, though it has not demonstrated the power to restore youth and most historians dispute the veracity of Ponce de León's discovery. Pythia, also known as the Oracle at Delphi was the high priestess of the Temple of Apollo. She delivered prophesies in a frenzied state of divine possession that were "induced by vapours rising from a chasm in the rock". It is believed that the vapors were emitted from the Kerna spring at Delphi. The Greek myth of Narcissus describes a young man who fell in love with his reflection in the still pool of a spring. Narcissus gazed into "an unmuddied spring, silvery from its glittering waters, which neither shepherds nor she-goats grazing on the mountain nor