Not much remains of Abergavenny Castle except for an impressive stretch of curtain wall on either side of the gatehouse on the northwest side. It was the site of a notorious event in 1175 when the Norman lord invited his Welsh rivals for a Christmas dinner and had them massacred. Frequently besieged but never taken, the castle was wrecked by royalist forces in 1645 during the Civil War in order to keep it out of parliamentary hands.
The castle keep, converted into a hunting lodge by the Victorians, now houses the small Abergavenny Museum. It tells the history of the castle and the town, and includes re-creations of a Victorian Welsh farmhouse kitchen, a saddlery workshop and Basil Jones' grocery shop. The latter was transferred when it closed in the 1980s and makes a fascinating display, with many items dating back to the 1930s and '40s.