Reginald’s Tower, Waterford city, Ireland. This impressive late 12th century tower was an integral part of Waterford city’s defences. It was built on the site of an earlier wooden fortification and it is probably named after Ragnar (Reginald), a former Hiberno-Norse king of the city. This would make it the only surviving Irish building that retains its original Viking name. During its long and rich history the tower has had many uses including as a mint, a prison and a military store. It now houses a small but excellent museum.