The Groß Raden Archaeological Open Air Museum is in a depression that borders directly onto the lake of Groß Radener See. On a peninsula in front of that lies its circular castle rampart, visible from afar, which has a diameter of 50 metres. From 1973 to 1980 extensive excavations were carried out here, led by Ewald Schuldt, during the course of which the remnants of a Slavic settlement dating to the 9th and 10th centuries was unearthed. The fort has been reconstructed based on the excavations and established as an archaeological open-air museum. It has been enhanced by finds from the Slavic castle of Behren-Lübchin.
References:Château de Niort is a medieval castle in the French town of Niort. It consists of two square towers, linked by a 15th-century building and dominates the Sèvre Niortaise valley.
The two donjons are the only remaining part of the castle. The castle was started by Henry II Plantagenet in the 12th century and completed by Richard the Lionheart. It was defended by a rectangular curtain wall and was damaged during the Wars of Religion. In the 18th century, the castle served as a prison.
The present keeps were the central point of a massive fortress. The southern keep is 28m tall, reinforced with turrets. The northern tower is slightly shorter at 23m. Both are flanked with circular turrets at the corners as well as semicircular buttresses. Each of the towers has a spiral staircase serving the upper floors. The Romanesque architecture is of a high quality with the dressed stones closely jointed.