Located beside Beitou Hot Spring Park Thermal Valley is one of the sources supplying the area rsquo;s hot springs. The sulfuric steam that blankets the valley year-round gives the valley a frightening quality giving rise to nicknames like ldquo;Ghost Lake. rdquo; The springs here have the highest temperatures of any in the Datunshan volcano group. With its surreal sulfuric atmosphere it rsquo;s no wonder Thermal Valley was considered one of the ldquo;12 great sights of Taiwan rdquo; during the Period of Japanese Occupation! The ldquo;Beitou rocks rdquo; (aka Hokutolite or Anglesobarite) in Thermal Valley contain the radioactive element radium. Out of the many thousands of minerals existing in the world they are the only ones named after a place in Taiwan and can be found in only two places: Beitou and Tamagawa Japan. In recent years the ldquo;Beitou Rock Conservation Area rdquo; has been established to ensure the protection of these natural rarities. Thus when visiting Thermal Valley you not only get to experience ldquo;hell rdquo; but also gain insight into some rare radioactive rocks! Water temperature in Thermal Valley rsquo;s hot springs ranges from 80-100℃. The sodium carbonate springs tend to be corrosive and have come to be known as ldquo;Green sulfur springs rdquo; and ldquo;Sulfur heads. rdquo; Visitors used to boil eggs in the hot springs but the practice has since been prohibited mdash;not only to protect the water quality but to keep tourists from falling in and boiling themselves!