St Cybi’s church in Holyhead stands inside Caer Gybi, one of the few Roman forts in Europe walled on just three sides, with the sea as the fourth. The fort is late Roman, and its north-east corner tower still stands 7.9 metres high; it’s free to walk in. Thomas Telford’s road from London, now the A5, ends at his Admiralty Arch of 1822 to 1824, built to mark George IV’s visit on his way to Ireland in 1821. The breakwater, finished in 1873, is the longest in the UK at 1.71 miles, and in good weather you can walk out to the lighthouse at the end. To the west are Holyhead Mountain and the seabird cliffs of South Stack.
