Heritage Open Day: A purpose built ammunition store constructed in 1749 to provide safe storage of explosives required by the military garrison at the Barracks. Previous storage arrangements in the flankers of the Brass Bastion proved unsatisfactory during preparations for an expected attack by the Jacobite forces in 1745, when most of the gunpowder was discovered to be damp and unusable. The new Magazine incorporated features designed to ensure protection against damp and potential explosion. It is built of local sandstone and is surrounded by a high wall. The walls of the vaulted, windowless structure are re-enforced by eight heavy buttresses, intended to direct explosion safely upwards.