Aquae Calidae, Bulgaria well as from Kabyle, Mesambria (now Nessebar), Odessos, Histria, Tomis, Byzantium, Abdera, Maroneia and the islands of the Aegean, the oldest from Apollonia Pontica from the 5th century BC. The first baths at the Sanctuary of the Three Nymphs originated when the Roman Empire under Lucullus conquered the region, during the Third Mithridatic War in 72 BC. Under Trajan (98-117) nearby Anchialos became the administrative centre of the region and the baths were expanded and extended with two more swimming pools. During this time the Via Pontica was built connecting Constantinople via Deultum, Anchialos, Aquae Calidae with Dorostorum and Sexaginta
Geothermal energy a renewable energy source like geothermal. But as a result of government assisted research and industry experience, the cost of generating geothermal power has decreased by 25% over the past two decades. In 2001, geothermal energy costs between two and ten US cents per kWh. Hot springs have been used for bathing at least since Paleolithic times. The oldest known spa is a stone pool on China's Lisan mountain built in the Qin Dynasty in the 3rd century BC, at the same site where the Huaqing Chi palace was later built. In the first century AD, Romans conquered "Aquae Sulis",