The seventeenth-century walls of Derry are the finest example of a completely intact walled city in Ireland, and arguably in the British Isles. The circuit is 1.5 kilometres around, standing six metres high with a walkable parapet along almost the entire length. You can walk the full loop in about 30 minutes, looking down into the old city on one side and out over the Bogside on the other.
The walls were built between 1613 and 1618 as defences for the new plantation settlement. Four of the original seven gates survive: Shipquay Gate, Ferryquay Gate, Butcher Gate, and Bishop Gate, each now set within its original opening. The cannon at various points are not decorative — they were put here to fight. Entry is free, and the walls are accessible at multiple points around the circuit.