Fort Hoofddijk was built in 1879 as one of the fortifications around Utrecht that formed part of the Nieuwe Hollandse Waterlinie, or 'New Dutch waterline'. This defense line made use of inundating parts of Holland to stop the advance of the enemy, but because Utrecht was on relatively high ground, it needed an additional ring of fortifications.
Today the Botanical Gardens of Utrecht University are located at the fortress site. It’s a beautiful place for a long walk along rare species of plants and flowers.
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.