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
Aquae Regiae Aquae Regiae Aquae Regiae was a Roman town in the Roman province of Byzacena, during the Roman Empire and into late antiquity. The Latin adjective referring to it is "Aquaregiensis". The bishop of this town, Massimiano, participated in the 411 Carthage conference, between the Catholic bishops and Donatist bishops of Africa and was at the other Carthaginian council of 419. Another bishop was among the Catholic prelates summoned in 484 to Carthage by the Arian king of the Vandals, Huneric. The bishop of the town was exiled after this conference. Today Aqua Regie survives as a titular bishopric of the