Bad Dürrnberg sits above Hallein and has been producing salt since at least 600 BC, making it one of the oldest mining sites in the Alpine world. Celtic tribes worked the brine deposits before the Romans arrived; the excavated finds, including wooden tools and clothing preserved in salt, are displayed at the Keltenmuseum Hallein below. The Salzwelten Hallein offers underground mine tours (entry around EUR 15–20). Reach it by bus or car from Hallein, 15 minutes south of Salzburg by regional train. Combine with the Keltenmuseum and the Barmsteine rock towers for a half-day excursion.