GASTEIN, in the province of Salzburg, Austria, a side valley of the Salzach, about 25 m. long and 1 a m. broad, renowned for its mineral springs. The valley lies at an elevation of between 3,00o and 3,50o ft. and is traversed by the river Gasteiner Ache and the railway which pierces the Hohe Tauern. The principal settlements in the valley are Bad-Gastein and Hof-Gastein. Bad Gastein is a very celebrated watering-place situated on a shelf between the upper and lower valleys of the Ache at a height of about 3,30o ft. Its thermal springs have a temperature of I 13-120° F, are mineral-bearing and radioactive and used as baths for the treatment of nervous diseases, rheumatoid complaints and senile debility. Their medical value has been known since the 7th cen tury but they were popularized by the visits of Wilhelm I. of Prussia and the Austrian Imperial family. On several occasions, notably during the negotiation of the Austro-German treaty in 1879, the town has been the scene of historic political conferences. It is also celebrated for its magnificent waterfalls, the upper, the Kesselfall (196 ft.) and the lower, the Barenf all (296 ft.). Pop. (1923) 2,67o. Hof-Gastein, the capital of the valley commune, lying at a lower level is also a spa, the waters being conveyed from Bad-Gastein by a conduit. At one time it was, after Salzburg, the richest place in the province owing to its gold and silver mines, worked from the Roman period onwards until the 1 7th century, since when they have been disused. Pop. (1923) i ,040.