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:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.