From a sixty-meter-high rocky pier above the confluence of the Brestanica stream and the Sava river, Rajhenburg Castle has been controlling the surrounding area for centuries. The castle building was built between 1131 and 1147 by the powerful owner of the estate, Archbishop Konrad of Salzburg, as evidenced by the oldest, Romanesque part of the building. For centuries, the building and the associated estate were managed by ministeriales, who were named after the castle – the Rajhenburg family. This was an influential family that achieved the title of knight in the 15th century. After their extinction, their successors added more modern elements to the building and gradually gave it the appearance we admire today. In 1881, Rajhenburg was purchased by Trappist monks and converted into a monastery, which operated until the occupation in April 1941, when the German occupation authorities established a camp for the expulsion of Slovenes in the castle and its associated outbuildings. In 1947, the Trappist order was dissolved and the castle was nationalized. A year later, in June, the Correctional Institution for Women was opened, and later other penal institutions. Since 1968, when an exhibition on Slovenian exiles was opened in it, it has been primarily intended for museum and event activities.
After the denationalization process was completed in 2004, the castle is owned by the Municipality of Krško, and the completely renovated building is now managed by the Krško Cultural Center. During various events (concerts, theater performances, lectures, etc.), visitors can learn about the history of the castle, the town, and the entire area at permanent and temporary exhibitions. By walking through the building, they gain insight into the development of castle architecture from Romanesque, Gothic, and Renaissance to modern times. The castle boasts two chapels: Romanesque from the 12th century and Gothic from the 16th century. The Renaissance living area with a luxurious hall is completed by a room with rich fresco paintings. The museum exhibitions of the Museum of Contemporary History of Slovenia offer us an insight into the history of the Trappist monks, the fate of Slovenian exiles and the time when various penal institutions operated in the castle. Visitors can also see castle furniture from the collections of the National Museum of Slovenia, views of Brestanica from the end of the 19th century and motifs from social and community life presented on the presented postcards, and the castle also exhibits noble medals from the Olympic Games and world championships of the most famous Brestanica athlete Primož Kozmus. The Renaissance hall is enriched by the works of the academic painter Jože Ciuha, and art exhibitions are also organized in the large hall, which is marked by a four-winged Gothic window with a stone cross. Rajhenburg Castle is one of the most important monuments of medieval castle architecture in Slovenia, which is why we place great emphasis on the building history of the building.
The castle cellar houses a sparkling wine library, and the museum shop offers exhibition catalogues, numerous local products and Brestanica chocolate. The completely renovated castle with its picturesque location and exemplary renovated interior is also an excellent setting for wedding ceremonies, and modern equipment makes the entire building accessible to people with disabilities.
The complete renovation of the castle building, which took place between 2010 and 2012, was financed within the framework of the Operational Programme for Strengthening Regional Development Potentials for the period 2007–2013, development priorities Connecting natural and cultural potentials − priority directions Networking cultural potentials.