The 47-metre-tall belfry is standing in the center of Béthune. The Belgian border can be seen from the top. The chime of the belfry is composed of thirty-six bells. A belfry has stood on the site since 1346. The current belfry plays melodies every 15 minutes, including the ch'ti (regional patois) children's lullaby min p'tit quinquin (my little darling). In 2005, the belfry was inscribed on the UNESCO World Heritage List as part of the Belfries of Belgium and France site, because of its architecture and testimony to the rise of municipal power in Europe.
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.