7264834 Great Siege Tunnels, Gibraltar. 18th century (photo); Gibraltar; (add.info.: Great Siege Tunnels, Gibraltar. A tableau showing two soldiers at work on a tunnel face. The approximately 277 metre long tunnels known as the Great Siege Tunnels were hewn from solid limestone using sledgehammers, crowbars and gunpowder during the 1779 - 1783 siege by Spain and France. Their completion allowed British gunners to fire onto the besieging troops.); Photo by Ken Welsh. All rights reserved 2022.