Quarried out of the natural bedrock, The Temppeliaukio church is one of the most popular tourist attractions in the city; half a million people visit it annually. The interior walls are created naturally by the rock. The church was designed by architects Timo and Tuomo Suomalainen and opened in 1969. The interior was excavated and built into the rock but is bathed in natural light entering through the glazed dome. Due to its excellent acoustics the church is a popular venue for concerts.
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.