Caer y Twr

Caer y Twr (meaning 'fort of the pile/heap') is an Iron Age hillfort situated atop the summit of Holyhead Mountain in Anglesey, Wales[1]. The fortification occupies a commanding position among rocky outcrops, making it ideally positioned for defence and surveillance[1]. Archaeological evidence indicates it functioned as a watchtower and signal station, potentially designed to alert lower-lying settlements to approaching maritime threats from the Irish Sea[1]. Some researchers propose the site may have served as a lighthouse, given its elevated position overlooking busy shipping lanes[2].