Castle Bogensperk, a classic example of renaissance architecture in Slovenia, was built on bedrock amidst woods, on the 412 meter high ridge of Strmec above Dvor near Smartno pri Litiji, looking towards Carinthia and Styria.
Most likely it was the Wagen family who gave the castle its current form after an earthquake in 1511. After Jurij Wagen's death in 1630 the castle changed several owners until 1672, when it was bought and thoroughly renovated by Janez Vajkard Valvasor. Castle Bogensperk is a rectangular building with four two-storey wings enclosing a courtyard. Facing the courtyard from the upper floor there are two walls of arcades. The northwest corner prominently features a squat tower like building, which was probably the original Gothic tower palace, later embedded in the walls of the current building. The other three towers are round in the east and west corner and rectangular in the south corner. The Chapel of the Blessed Virgin Mary can be found on the ground floor of the castle. Throughout its history the appearance of the castle has remained similar to other Carniolan castles from the 16th and the 17th centuries. A special attraction can be found in the basement of the castle where a well was carved directly into the bedrock.
In the middle of the 19th century the castle underwent several reconstructions, when the then owners, the noble family of Windischgraetz, built a neo-Roman biphore in the south wing and a neo-Gothic Chapel of the Blessed Virgin Mary on the ground floor.