The Eisriesenwelt (German for "World of the Ice Giants") is a natural limestone and ice cave located in Werfen, Austria, about 40 km south of Salzburg. The cave is inside the Hochkogel mountain in the Tennengebirge section of the Alps. It is the largest ice cave in the world, extending more than 42 km and visited by about 200,000 tourists every year.
The first official discovery of Eisriesenwelt was by Anton Posselt, a natural scientist from Salzburg, in 1879, though he only explored the first two hundred meters of the cave. Before his discovery, the cave was known only to locals, who, believing that it was an entrance to Hell, refused to explore it. In 1880, Posselt published his findings in a mountaineering magazine, but the report was quickly forgotten.
Alexander von Mörk, a speleologist from Salzburg, was one of the few people who remembered Posselt's discovery. He led several expeditions into the caves beginning in 1912, which were soon followed by other explorers. Von Mörk was killed in World War I in 1914, and an urn containing his ashes is inside a niche in the cave. In 1920, a cabin for the explorers, Forscherhütte, was built and the first routes up the mountain were established. Tourists began to arrive soon after, attracted by the cave's sudden popularity. Later another cabin, the Dr. Oedl House, and paths from Werfen and Tenneck were constructed.
In 1955 a cable car was built, shortening the 90-minute climb to 3 minutes. Today the Eisriesenwelt cave is owned by the National Austrian Forest Commission, which has leased it to the Salzburg Association of Cave Exploration since 1928. The Forest Commission still receives a percentage of the entrance fees.