Bangor

Comgall's monastery of 558 was one of the great schools of Europe: Columbanus and Gall both left from here for the Continent, and the Antiphonary of Bangor is among the oldest surviving Irish manuscripts. The Vikings burned it repeatedly. It is now a seaside town on Belfast Lough.

• Nendrum Monastery · Three concentric drystone enclosures, a round tower stump, and a sundial from around 900. Beside them, dug out of the shore, the oldest excavated tide mill anywhere in the world — tree-ring dated to 619, rebuilt in 787.

All of these are pinned on the Hidden Ireland map.