Eisriesenwelt

The Eisriesenwelt near Werfen in Salzburg state is the world's largest accessible ice cave, with frozen galleries extending approximately 42 kilometres into the Tennengebirge massif. Only the first kilometre is open to visitors, but that section contains towering natural ice columns, arched ice tunnels, and formations christened by early explorers in the 1870s. The cave entrance is reached by cable car and a 15-minute uphill walk from the Werfen valley.