These rings can be found all over the Upper Rock Nature Reserve in Gibraltar. They were used by the military in days gone by to haul cannons up to their positions around the top of the Rock.
I cannot imagine how difficult that must have been – it’s hard enough hauling myself up there. The strength and ingenuity of the military is plain to see all over Gibraltar, with the fortifications and tunnels. We have the Royal Engineers to thank for much of them.