Waterford

Ireland's oldest city, founded by Vikings in 914. Reginald's Tower at the point of the triangle has stood for eight centuries and is the oldest civic building in the country still in use. Strongbow married Aoife here in 1170 and took Leinster as her dowry — the moment the Norman conquest became permanent.

• Hook Lighthouse · Raised between 1201 and 1240 by William Marshal to guide ships to his port at New Ross, with walls four metres thick. It is still working, eight centuries on — the second-oldest operating lighthouse in the world.
• Reginald’s Tower · The oldest civic building in Ireland, and the only urban monument in the country still carrying a Norse name. Strongbow married Diarmait Mac Murchada’s daughter Aoife here — the marriage that tied Leinster to the Normans.

All of these are pinned on the Hidden Ireland map.