According to Wikipedia: "The Széchenyi Thermal Bath in Budapest is the largest medicinal bath in Europe. Its water is supplied by two thermal springs, their temperature is 165 °F and 171 °F, respectively.
"Components of the thermal water include sulphate, calcium, magnesium, bicarbonate and a significant amount of fluoride acid and metaboric acid. Medical indications are on degenerative joint illnesses, chronic and sub-acute joint inflammations, as well as orthopaedic and traumatological post-treatments."