The parish church of Saint Tanwg at Llandanwg is situated just behind the beach in the sand dunes just 20 metres above the high tide mark. The church is medieval, probably dating from the 13th century, however there are three 5th to 6th century inscribed stones and two stones with inscribed crosses inside the building which indicates much earlier activity. It has probably been a place of worship since the Age of the Saints, possibly as early as the first part of the 5th century. Much of the churchyard is buried in sand. The churchyard contains the war graves of a Royal Welsh Fusiliers soldier and Royal Garrison Artillery officer of World War I.
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.