The round bastion was once the largest part of the defence system of the medieval castle, its diamater is more than 33 metres. It can be clearly identified on an engraving dating back to 1541, it was partly destroyed in 1686. By the end of the 19th century not too much was visible from it, since it was covered by a hill. The gate tower dates back to the medieval ages, its ground floor is original. Both buildings were restored in the 1960-s.