The ruin Hornstein is located in the Lauchert Valley, about 4 km northeast of Sigmaringen. In 1247 Burg Hornstein, the ancestral seat of the eponymous noble family, was first mentioned in a document. The castle experienced several development phases until it was rebuilt into a stately Baroque palace around 1700. From 1818 she was a Hohenzollerische "Breeding and correctional institution". In 1873 the plant was sold for demolition.