The Heraion was a sanctuary dedicated to the goddess Hera, situated 8 kilometers from Argos. Built on the southern foothills of the Euboian mountain range, it included ritual sites like the Eleutherian Water for purification and the river Glykeia. Excavations revealed its connection to Mycenaean times and its importance grew from the 8th century BC, becoming a key religious and political center for Argos.
The sanctuary featured a monumental stairway leading to terraces with structures like a Doric stoa and a new temple designed by architect Eupolemos in 420 BC, housing renowned sculptures. Additional structures included an altar and a hypostyle hall, reflecting its significance in Hellenistic and Roman eras. The site remained revered by the Argives until late antiquity, reflecting its enduring importance in Greek religious life.
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.