Bad Gastein (; formerly Badgastein; Southern Bavarian: Bod Goschdei) is a spa town in the district of St. Johann im Pongau, in the Austrian state of Salzburg. Picturesquely situated in a high valley of the Hohe Tauern mountain range, it is known for the Gastein Waterfall and a variety of Belle Époque hotel buildings. Geography Bad Gastein is located in the historic Pongau region, the municipal area of about is the largest in St. Johann im Pongau District. It stretches along the upper Gastein Valley following the course of the Gastein Ache creek, a right tributary of the Salzach river. The valley separates the Hohe Tauern Ankogel Group in the east from the Goldberg Group in the west. The town centre is located at the Gastein Falls, about above sea level. It is characterised by numerous historic multi-storey hotel buildings erected on the steep slopes. The Gastein municipality comprises the cadastral communities of Badgastein, Böckstein, and Remsach. Its southern parts belong to the Hohe Tauern national park. Transportation The Gastein valley is accessible by the Tauern Railway, a major railroad running from Schwarzach-Sankt Veit in the north across the Alpine crest through the Tauern Tunnel to Spittal an der Drau, Carinthia in the south. Frequent EuroCity and InterCity trains going along this route connect Bad Gastein with many Austrian cities like Vienna, Linz, Salzburg and Graz along a single circuit. The B167 Gasteiner Straße highway also passes right through the Gastein valley. Through traffic from the northern branch-off at Lend in the Salzach valley passes the lower municipalities of Dorfgastein and Bad Hofgastein before reaching the Bad Gastein centre. However, in Böckstein at the head of the valley, the continuation southwards to Mallnitz in Carinthia requires cars to roll onto a shuttle train (Autoverladung) for a short trip through the Tauern Tunnel. Spa and therapy The name "Bad" means "spa", reflecting the town's history as a health resort. The local Heilstollen (literally 'healing tunnel') thermal spring water earned the town its early fame. Theophrastus Parcelsus (1493–1541) had studied the spring water to discover its secrets. Marie Curie (1867–1934) and Heinrich Mache (1876–1954) helped to discover that it contained radon and as a result radon therapy began in the town. Radon inhalation therapy at the Gasteiner Heilstollen began as a result of further investigation into the anecdotal experiences of silver miners who noticed improvements in symptoms from various ailments including arthritis.