Geothermal heating a total capacity of 15 GW extracted 88 PJ of heat energy for space heating. Global ground-source heat pump capacity is growing by 10% annually. Hot springs have been used for bathing at least since Paleolithic times. The oldest known spa is a stone pool on China's Mount Li built in the Qin dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. Geothermal energy supplied channeled district heating for baths and houses in Pompeii around 0 AD. In the first century AD, Romans conquered Aquae Sulis in England and used the
Celtic animism foci for healing cults: Sulis was prayed to as a healer at Aquae Sulis and the goddess Arnemetia was hailed as a healer at Aquae Arnemetiae. Nemausus, for example, was not only the Gallic name for the town of Nîmes but also that of its presiding spring-god. He had a set of three female counterparts, the Nemausicae. In the same region, the town of Glanum possessed a god called Glanis: an altar from a sacred spring is inscribed 'to Glanis and the Glanicae'. Meteorological patterns and phenomena, especially wind, rain and thunder, were acknowledged as inspirited and propitiated. Inscribed dedications