A summit cross () is a Christian cross on the summit of a mountain or hill that marks the top. Often there will be a summit register (Gipfelbuch) at the cross, either in a container or at least a weatherproof case. Various other forms of marking or symbol such as cairns, prayer flags or ovoos may be found around the world on passes and hills, in particular on sacred mountains. In the Italian Alps a Madonna is sometimes placed at the summit instead of a cross. Summit crosses are normally about two to four metres high and are usually made of wood or metal. In April 2010, the world's first glass summit cross was erected on the Schartwand (2,339 m) in Salzburg's Tennengebirge mountains. Summit crosses are mainly found in Catholic regions of the Alps, especially in Austria, Switzerland and Bavaria, mountainous regions of Poland, but also in America, in areas with both Protestant and Catholic populations. In Slovenia, summit crosses were traditionally placed on mountaintops as symbols of faith, but their numbers were limited during the communist regime in Yugoslavia. They usually stand on mountains whose summits are above the tree line, but they are also found in the German Central Uplands, for example in the Black Forest on the Herzogenhorn. History By the end of the 13th century a few large crosses had been erected in passes and on hills. Examples from this period include the Confin Cross in St. Valentin on the Mals Heath, which also acted as a boundary marker, or crosses on the Arlberg, the Gardena Pass or Birnlücke. An early example of a large cross, visible from the valley floor, being set up on a mountain top, occurred during the first successful climb of Mont Aiguille in 1492, when three crosses were put up at the corner of the summit plateau. In the 16th century crosses were erected with increasing frequency on mountain peaks, especially for the purpose of marking alpine pasture and municipal boundaries. In the 17th century, especially during the Thirty Years' War, these religious symbols gained importance. The crosses of this period were mostly simple wooden ones hewn from branches found near the site, or house crucifixes. During this time crosses were often made with two cross beams in the form of so-called patriarchal crosses (or Scheyern crosses). These "weather crosses" were intended to supersede the old pagan superstitions associated with