Kahlenberg

The Kahlenberg is a hill located in the 19th District of Vienna, Austria, offering a view over the entire city. Parts of Lower Austria can also be seen from Stefaniewarte at the peak. The mountain is mostly flysch, which is composed of quartz, limestone, marl, and other conglomerates. There are two terraces on the mountain: one at a small church called St. Josef and one at a restaurant. The Kahlenberg is also notable as the place where Jan III Sobieski, King of Poland launched his attack on the Turkish forces during the second Turkish Siege of Vienna. Additionally, Albert Einstein, Otto Neurath, and other mathematicians and physicists made the first plans for what would later become the International Encyclopedia of Unified Science on this mountain