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
The Skystone From there he leaves for Aquae Sulis, where Britannicus owns a villa. On the road to Aquae Sulis, Varrus encounters several bandits who attempt to murder him. He later, after another assassination attempt, finds out that these men had been hired by the Senecas. He finally arrives in Aquae Sulis and encounters Britannicus's brother-in-law Quintus Varo. Varo invites Varrus to his villa. At the villa, Varrus meets Caius Britannicus's sister Luceiia. Also while at the villa Varrus encounters a Welsh hunchback Cymric. Varrus demonstrates the African bow which his grandfather had left in his collection of weapons. Luceiia and Varrus