Caer y Twr

Caer y Twr (meaning 'fort of the pile/heap') is an Iron Age hillfort atop the summit of the Holyhead Mountain in Anglesey, Wales [1]. 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 [1]. The entrance to the fort was through a rocky gully [1]. 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 [1].