The Iron Tower (Eisenturm) is a medieval tower dating to the early 13th century, and modified in the 15th century, which with the Wood Tower and the Alexander Tower is one of three remaining towers from the city walls of Mainz, Germany. Its name derives from the Iron Market (Eisenmarkt), which was held in the immediate vicinity until the 19th century.
The Iron Tower served as a watchtower and gate to the city, and later as a gaol. It was badly damaged in World War II and reconstructed in the 1960s. Today it houses various organizations and art projects and is used for art exhibitions.
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.