Caer Gybi
One of only three walled Roman forts in Europe, this small 3rd-century structure with three walls and towers overlooks Holyhead's harbor and watched for Irish raiders until abandoned at the fall of the empire. The church of St. Cybi, now inhabiting the interior grounds, dates mainly to the 16th century. Heavily damaged by Oliver Cromwell's soldiers during the English civil wars, it was restored in the mid-19th-century and houses impressive Carrara marble statues and stained-glass windows. A second church on the south end was converted into a school for poor children in the 1700s.
