Dachstein Giant Ice Cave, Natural monument and ice cave at 1406 meters elevation in Obertraun, Austria.

The Dachstein Giant Ice Cave is an ice cave in the Dachstein massif above Obertraun, with a known length of 2,700 m, of which 800 m is open to visitors. Its three surface openings include the tour entrance at 1,421 m and the Große Windloch exit at 1,459 m. The tour route passes the King Arthur Dome, the lowest point at 1,384 m, then the ice section with the Parsival Dome and Tristandom, where a suspension bridge crosses an ice abyss.

A local legend, probably untrue, credits Peter Gamsjäger of Obertraun with finding the cave in 1897 while searching for lost cattle; residents likely knew it far earlier. On 17 July 1910 Hanna and Hermann Bock of Brno and Georg Lahner of Linz crossed the Great Ice Abyss and entered deeper passages, the date taken as its official discovery. Guided tours began in 1912, electric lighting followed in 1928, and a new entrance was opened in 1952.

The cave belongs to the UNESCO World Heritage site of Hallstatt-Dachstein/Salzkammergut and displays layers from the ancient Tethys Ocean period. Visitors can observe how geological processes shaped this mountain region over millions of years.

The cave is reached by the Dachstein Krippenstein cable car to Schönbergalm, then an asphalted footpath leads to the entrance at 1421 m and the exit at the Great Windhole at 1459 m. Tours run in the summer months and last just under an hour. Warm clothing and sturdy shoes with non-slip soles are recommended.

The ice masses inside contain about 13,000 cubic meters of frozen water, with certain layers dating back approximately 500 years based on pollen analysis. This ancient ice offers insight into climate conditions from centuries past.