Bederkesa is a medieval castle built originally in the 12th century. Its original owners, the counts of Bederkesa, lost their fief in 1381. For more than two centuries, the City of Bremen became owner of this castle and its surrounding subjects. As a symbol of sovereignty, they have constructed a Roland statue which is still standing in front of castle. Until 1859, this castle served as administrative centre of its surrounding area. In 1881, it was sold to local investors who converted it into a hotel. This hotel, however, became ramshackle and was deemed to demolition, when the local county administration bought it in 1975, spending much money for reconstruction. Since 1982, the castle serves as museum of local archeology. Remains of prehistoric and medieval houses have been dug from three abandoned villages, Fallward, Feddersen and Flögeln. These Anglo-Saxons moved to England around 450 AD and left their villages uninhabited.
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.