Hakasalmi Villa was built in 1843 by the procurator and privy counsellor Carl Johan Walleen as a combined city and country residence. The architect was E.B. Lohrmann from Berlin. Two wings were added to the front of the main building in 1847, the north one served as a bakery and the south one as a greenhouse. The villa was surrounded by a large English garden.
The municipality of Helsinki bought Hakasalmi from Aurora Karamzin in 1896. After her death the historical museum of state was moved to the villa. Since 1911 it has been owned by Helsinki city museum. Today there are changing exhibitions. The villa itself is one of the rare empire-style buldingins still existing in Helsinki.
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.