Derry

Colmcille's foundation of 546, rebuilt as a walled city in 1613 by the London livery companies who financed it — hence Londonderry, and hence the argument over the name that has never stopped. Its seventeenth-century walls have never been breached: thirteen apprentice boys shut the gates against King James in 1688 and the city held out for 105 days. 'No Surrender' entered the language here.

• Grianán of Aileach · The stone ring-fort of the Northern Uí Néill, 250 metres up above Lough Swilly, with terraces inside its walls for the assembled warriors of Ailech.
• Rathmullan · The pier from which the Earls sailed in September 1607 (Hugh O'Neill, Rory O'Donnell and ninety followers) never to return. Ulster's history pivots here.

All of these are pinned on the Hidden Ireland map.