The Sontheim Cave
The Sontheim Cave is a former river cave estimated to be about 3 to 5 million years old.
The entrance hall:
This enormous hall has a length of 45 metres and a width of 16 metres. The walls are heavily weathered. In winter, considerable ice formations often grow in this first hall. When it is cold outside the cave in winter, heavy cold air then remains on the floor of the entrance hall and when dripping water seeps into the cave, ice is formed.
Fig. 3: Ice formations
The bat gate:
The main passage now continues in a north-westerly direction until it reaches a narrowing in the cave. There, an iron gate, the „bat gate“, is located. This gate serves to protect the bats hibernating in the cave and is constructed in such a way that bats can fly through unhindered. From 1 November to 1 May, the bat gate remains closed. Since 2019, a light barrier has been installed to register the bats‘ entries and exits.
Fig. 4: The bat gate
The Pug Hall:
The Pug Hall is characterised by beautiful, well-preserved stalactites. This 26-metre-long hall is called the „Pug Hall“. The name comes from a species of bat that hibernated here in large numbers until the 1950s. Today, however, pug bats are all but extinct in Germany. Up to here, the incoming outside air has an influence on the temperature, so ice can form in severe winters. At the end of the hall is the weather barrier – a narrow corridor leading to the next hall. From the weather boundary onwards, there is no more influence, due to the outside temperature.
The organ and shepherd’s wall:
At the end of the narrow passage, you enter another hall. From here on, there is a constant temperature of + 7° C all year round. Right at the beginning, at the top left, there is a stalactite curtain called the „organ“. On the right side, behind the stalagmite, skeletal remains of a human were found in 1976. They are dated to the Celtic period, between 845 and 715 BC.
The wall opposite is called the „shepherd’s wall“. It is entirely covered with stalactites, in which, with a little imagination, one can make out a shepherd with sheep on a mountain pasture. Some of the stalactites are covered with a thick black layer of soot, which dates back to the time when the cave was lit with pitch torches.
The cross of the cave:
The path continues downwards in a westerly direction to the Alemanni grave. An early Alemannic burial site was found here in 1976 (see separate section).
At this point, two ceiling crevasses cross, so that this space is also called the „Kluftenkreuz“. The oldest picture of the cave exists from this place, drawn on 25.07.1828.
Fig. 5: The oldest picture of the cave
The final hall:
This final hall of the cave is 30 metres long and 14 metres wide, with three shafts leading up to the top. The chimney is 33 metres high and branches out into several horizontal passages. In this last hall, the entire floor is covered with a tough layer of clay. More than 150 years ago, cave clay was mined here and used to clean and polish pans and brass vessels. It can be assumed that ore was also mined here. At the end of the hall, you are 34 metres lower than at the entrance and 8 metres above the valley floor.
On the right, in a niche, there is a stalactite called „The Bell“. This once grew on the clay floor, but later the floor sank so that the foot of the stalactite now hangs in the air. If you look around the north side of the room, you can still clearly see how high the clay once was.
Fig. 6: The bell
On the left side of the hall, halfway up the wall, is a niche containing what are probably the most beautiful stalactites in the cave – the so-called „waterfall“.
Fig. 8: The waterfall
The Sontheim Cave has a total passage length of 530 metres, although the main passage we visited is only 192 metres long. The total height difference from the highest to the lowest point is 54 metres.
Barbara Kreuzer (abridged)
Further information in the brochure on Sontheim Cave, available at the cave ticket office.