Rock cannon

A rock cannon is a boulder or rock that has been drilled with holes, partially filled with black powder, and ignited to produce explosive sounds during traditional festivities. These devices are primarily found in the slate quarrying areas of Gwynedd in North Wales, where 235 sites had been recorded by 2001. The firing of rock cannons was a customary part of social events and celebrations in north Wales from the late 18th century, often accompanying fireworks and bonfires. Such firings marked national or local events, including royal visits, notable births and marriages, and the opening of the Ffestiniog Railway and its Moelwyn Tunnel. The marriage of Albert Edward, Prince of Wales to Princess Alexandra of Denmark in 1863 was celebrated at the 13-hole cannon at Trefriw, where about 8cwt of gunpowder was consumed. The visit of the Duchess of Kent to Blaenau Ffestiniog saw a firing as late as 1951.