We are afraid that we can't offer you the whole site in your language. Here's just a short summery about our cave.
Nidlenloch (SO), located in the Weissenstein, the mountain of Solothurn, was mentioned in the literature for the first time in 1828.
The local population certainly knew of it for a much longer time. In that year, the alpinist and naturalist Franz Josef Hugi succeeded in progressing 350 m into the cave. In 1868, an engineer, Moser, created a 1 : 1,000 scale map and cross section of the part explored by Hugi. From 1889 to 1891, in a series of expeditions led by Forster and Rotschi, several small pits were descended with rope ladders. Exploration continued under the direction of Franz Held, who organized more than 60 expeditions up to 1909. The 396 m depth they attained made it at that time the deepest known cave in the world. Today, Nidlenloch remains the deepest cave in the Swiss Jura.
The entire cave was mapped in 1937 and 1938. This map, by Kormann and Kulli, showed 2.1 km of passage. The cave was the object of numerous visits in the following years, but it was not until 1975 that exploration efforts were renewed by the AGN (Arbeitsgemeinschaft Nidlenlochforschung, or the Nidlenloch Exploration Working Group). In 10 years of exploration, systematic research, and several digs, this group has been able to push the cave to 7.5 km lenght and 418 m depth.
This cave is formed in the "Sequanian" (Maim) limestones on the northern flank of the Weissenstein fold. The passages follow either the dip of the bedding planes toward the north, or the east-weststrike of the beds. Towards the middle of the cave is a horizontal network of partially labyrinthian galleries. Other parts of the cave also have typical fossil phreatic passage networks. Today, this cave is traversed by very local or temporary streamiets, which barely contribute to the current karst drainage. Galleries of modest dimensions are often interrupted by breakdown, or low points filled with clay, which points to an advanced age for the cavity. Despite the important elevation changes in this cave, pits are infrequent and their depth does not exceed 20 m. No large rooms and only rare flowstone speleothems are found here.
The easy access, modest technical difficulties (in the upper portions of the cave, several pits are permanently rigged) as well as the ambiance of a large and deep cave have made Nidlenloch one of the most visited noncommercial caves in Switzerland. Some 6,000 people, in search of adventure, enter this cave annually. This incursion of humanity is not without its negative secondary effects, such as a burden - or overburden - on the natural environment, trash accumulation, and the nearly annual intervention of the local cave rescue team. However, this influx of visitors also has a positive side, in that it concentrates a large number of visitors into a single cave, thereby protecting other lesser known caves. in this sense, the Nidlenloch plays the role of "sacrificial cave".
Quelle: "Karst und Höhlen der Schweiz", Christian Preiswerk und Andres Wildberger, Basel 1997. Speleoprojects ISBN 3-908495-05-9 (Hardbound) bzw. ISBN 3-908495-06-7 (Paperback)