Walls of Derry

The Walls of Derry were completed in 1619 and are 8 meters high by 9 thickness and 1.5 km in circumference - they are the only ones in Ireland that have been preserved virtually intact. They have 4 original doors and 3 new ones were added in the eighteenth and nineteenth centuries. The nickname "maiden city" is that no invador has managed to breach its walls. It's worth a walk around the ramparts for its magnificent cannons.