Prebischtor sandstone arch, 19th-century illustration. This natural rock formation is located in the Elbe Sandstone Mountains, in what is today the Czech Republic. The area is also known as Bohemian Switzerland or Czech Switzerland. This arch has a span of over 26 metres, and is the largest natural sandstone arch in Europe. Artwork published in 'Les arteres du globe' ('The Arteries of the Globe', 1888), a work on hydrology and geology by Paul Bory.