Belfast

A small castle town until the seventeenth century, then a Presbyterian and radical city, then the industrial engine of Ireland: linen, rope, tobacco and the largest shipyard in the world, which launched Titanic in 1912. It was the birthplace both of the United Irishmen and of unionism, and it spent thirty years at the centre of the Troubles.

• 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.