The Mourne Wall - built in the early 20th century - runs up the western and southern slopes of the mountain, joining a small stone tower at the summit. Also on the summit are the remains of two ancient burial cairns, one of which is the remains of the highest known passage tomb in Ireland. In Irish mythology the mountain was associated with the mythical figures Boirche and Slángha. It was later associated with, and named after, Saint Donard, who was said to have made the summit his hermitage. Up until the 1830s, people would climb the mountain as part of a yearly pilgrimage, which may have originally been a Lughnasadh (harvest) ritual. Royal Engineers camped on the summit for four months in 1826 as part of the Ordnance Survey's Principal Triangulation.