Eisriesenwelt Ice Cave, Werfen: History, Tour Route and Visitor Tips

Eisriesenwelt, the "World of the Ice Giants", is the largest ice cave on Earth. It runs for more than 42 kilometres inside the Hochkogel, a peak of the Tennengebirge range above Werfen, about 40 kilometres south of Salzburg in Austria. Only the first kilometre is coated in ice, and that frozen kilometre is exactly the part visitors walk through.

Discovery: Anton Posselt and Alexander von Mörk

The Salzburg naturalist Anton Posselt found the cave in 1879 and explored the first 200 metres. He published a report in 1880, but it was largely forgotten. The man who brought Eisriesenwelt back to life was the Salzburg speleologist Alexander von Mörk, who began leading expeditions in 1912.

Von Mörk was killed in the First World War in 1914. His ashes rest in a niche inside the cave, in the great hall that now carries his name. In 1955 a cable car was built that cut the 90-minute climb from the valley to about three minutes, and today roughly 200,000 people visit each year.

How the ice forms inside a limestone mountain

Eisriesenwelt is a limestone cave, not a tunnel through a glacier. The ice is made by the mountain's own breathing. In winter, cold air flows in through the entrance and freezes everything near it. In spring, snowmelt trickles down through cracks in the rock and freezes on contact with the chilled walls and floor, building the formations layer by layer.

In summer the airflow reverses: cold air drains out of the cave from deep inside, which keeps the ice from melting. That is why the chambers stay at or below freezing even in July, and why the ice is limited to the section closest to the entrance.

The guided tour: from Posselt Hall to the Ice Palace

All visits are guided and last about 1 hour 15 minutes, by carbide lamp along a route of roughly one kilometre. Highlights include:

• Posselt Hall, with the stalagmite called Posselt Tower and a cross marking the point where Posselt turned back.
• The Great Ice Embankment, a frozen wall about 25 metres high.
• Hymir's Castle, home of the formation known as Frigga's Veil or the Ice Organ.
• The Alexander von Mörk Cathedral, one of the largest rooms in the cave.
• The Ice Palace, about a kilometre in and 400 metres below the surface, where the tour turns back.

Photography is not allowed inside the cave.

How to get there and what to bring

Werfen is easy to reach by car, train or bus from Salzburg. From the visitor centre, the official route is:

1. About 20 minutes on foot to the lower cable-car station, partly through a tunnel.
2. Three minutes by cable car up the steepest section, a rise of about 500 metres.
3. About 20 minutes on a secured panoramic path to the entrance, at 1,641 metres above sea level.

Inside, the route climbs and descends about 1,400 steps, with a height difference of 134 metres — roughly the stairs of a 40-storey building. Allow about three hours for the whole outing. The cave is open daily from early May to the start of November; check the official Eisriesenwelt website for this year's hours.

Dress for winter even in August: warm layers, gloves and sturdy shoes with good grip. The temperature inside hovers around zero and usually stays below it.

Explore more: a different kind of cave within glacier ice; another Alpine attraction requiring current access checks.

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