St Donatus' Church (Crkva sv. Donata).
It was founded in the 9th century, when it was called the Church of the Holy Trinity, and given its present name six hundred years later in memory of a famous bishop.
The circular shape is typical of the early Byzantine age in Dalmatia.
It's become a sort of symbol of Zadar. Largely empty inside, but the excellent acoustics have made it Zadar's premier concert hall.