Caer y Twr (fort of the pile) is an Iron Age hillfort atop the summit of the Holyhead Mountain in Anglesey, Wales. The hillfort, which is situated among rocky outcrops, is ideally placed for defence and likely served as a watchtower and possibly as a signal tower. Some have speculated that it was built to alert a small fort in the modern town of Holyhead in the case of raiders coming in from the Irish Sea, while others have suggested that it may have been a lighthouse.
The hillfort is now mostly rubble, but its walls can still be made out, including a large stone rampart on the north and east sides which reaches 3 metres at points. The entrance to the fort was through a rocky gully. The footings of a tower were discovered when the site was excavated; its stones are believed to date from the 2nd to the 4th centuries.
Nestled below Caer y Twr is a group of several enclosed huts, named Cytiau Tŷ Mawr (the Holyhead Mountain Hut Circles), that also date from the 3rd to the 4th centuries, some of which still contain the accoutrements of life, such as hearths and shelves.
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.