The Balm ruins are the remains of a fortified cave dwelling in the Jura Mountains, in the municipality of Balm bei Günsberg. It is that canton's only cave stronghold and one of the few in Switzerland.
The stronghold was built 20 metres high in a natural cave of about 20 metres wide and 6 metres deep.
The outer wall was provided with two doorways and some narrow windows. The wet rock face was covered with a lining wall; and the rest was a simple two-story timber construction, which is shown evident by the presence of holes into which beams were inserted. While being restored, the presently visible wall openings were distorted from their original form. At a later stage in the building of the stronghold, a fortified, inhabited house with an inside width of 3.5 metres and a length of 29 metres was erected in the forecourt. Presumably this was a defensive fortification of some farming complex.
The entrance to the stone fortress stretched over a long, partly walled rise which is partly hewn from the rock. The connection between the forecourt and the fortress itself is still only incompletely reconstructed. The present-day rise is of modern source, and only partly represents its original state.
Excavations from the years 1939 and 1941 indicate that the place had been used as a habitation since early times.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.