in the Tennen Mountains. The most famous is the Eisriesenwelt near Werfen, which is about 42 km long and is the largest ice cave in the world. Its ice section is open to the public as a show cave. The best-known caves near valley level are the Brunnecker Cave on Lueg Pass, the Winnerfall Cave near Oberscheffau and the Trickl Cave near Abtenau. These are active water caves which can become flooded during snowmelt or other periods of high water level. Another important cave system is the Platteneckeis Cave–Berger Cave–Bierloch system in the northwest of the mountain block. This system drains towards the Brunnecker Cave, dropping through a height of over 1,000 metres. Other important caves are the Schneeloch on the Kuchelbergalm and the Eiskogel Cave, which crosses the mountain of the same name on the southern edge of the Tennen The Tennen Mountains are a preferred research region for the State Cave Research Association in Salzburg, which collects and publishes results of its research. New caves are continually being found, but even old, well-known caves sometimes reveal new secrets. Knowledge of the caves, and the routes that water takes through them, is important, particularly in terms of future water supply for the population and the protection of water resources. Walking and climbing Being a high plateau, the Tennen has numerous trails for the Alpine hiker. However, walkers need to be aware of the lack of water in the karst terrain and the dangers of getting lost in mist or fog. Alpine experience and a good level of fitness are basic pre-requisites, even though there are many mountain huts available. The precipices on the edge of the plateau offer the climber a wide scope of climbing options. The faces on the southern edge of the range, especially around the Werfener Hut and above Dr. Heinrich Hackel Hut are very popular due to their easy accessibility. In winter there are various ski touring routes, mainly crossing the plateau, but also extreme ski routes in some places. Huts Anton Proksch House (1,590 m) Dr. Friedrich Oedl House (1,575 m) Dr. Heinrich Hackel Hut (1,530 m) Edelweißer Hut (2,350 m) Elmaualm (1,520 m) Freilassing Hut (1,550 m) Gsengalm Hut (1,450 m) Gwechenberg Hut (1,365 m) Laufen Hut (1,725 m) Leopold Happisch House (1,925 m) Mahdegg Alm (1,200 m) Rossberghütte (1,000 m) Stefan Schatzl Hut (1,340 m) Werfen Hut (1,970 m) Long distance trails