A marble vein leads from Hintertux southwards to the Spannaglhaus, in which the cave system with its numerous natural wonders lies. In 1919, the then landlord of the Spannaglhaus, Alois Hotter, discovered the entrance to the cave. Exploration did not begin until around 1960. almost four years later, this unique cave and its surroundings were placed under nature conservation.

Thanks to the private initiative of the hut tenant Josef Klausner (1974-2003), part of the cave was opened to visitors in the entrance area on 1 July 1994. In the meantime, guided tours through the marble show cave take place all year round.

Central gneiss is the rock that the area around the Hintertux glacier is mostly made of, but it is impossible to form a cave in this rock. Due to the complicated tectonic situation of this area, a marble vein was intercalated between the gneiss rock during the Alpine mountain building. The cave system is located in this vein, which is about 25 m thick.

The entrance to this largest cave in Tyrol is directly under the Spannagelhaus and thus also the highest point of the cave system. The ventilation of the Spannagel Cave follows the chimney effect: the cave temperature is +2°C, if the outside temperature is lower, the air is drawn upwards and it blows out relatively warm at the entrance and vice versa.