Military tunnels in Gibraltar’s Rock, dug during the Great Siege.
The Great Siege Tunnels, also called the Upper Galleries, are military tunnels inside the northern end of the Rock of Gibraltar. Dug by the British from solid limestone during the Great Siege of Gibraltar in the late eighteenth century, they stand about 220 metres above sea level and are partly open to visitors.
The Great Siege Tunnels, known as the Upper Galleries, are a series of military tunnels inside the northern end of the Rock of Gibraltar, a British Overseas Territory. They were excavated by the British from solid limestone during the Great Siege of Gibraltar in the late eighteenth century, when France and Spain attempted to capture Gibraltar from Great Britain during the American Revolutionary War, in what became the fourteenth and final siege of Gibraltar. Artillery batteries were placed in galleries on the north face of the Rock to create overlapping fields of fire. The garrison needed to cover a blind angle on the north‑east side, and the only solution identified was to mount a gun on a rocky spur called The Notch. Because the cliff was vertical, Sergeant‑Major Henry Ince of the Military Artificers proposed digging a tunnel to reach it. Work began on 25 May 1782. The tunnels were dug mainly by hand using sledgehammers and crowbars, assisted by gunpowder blasts. A horizontal shaft was blasted for ventilation and later adapted as an embrasure for a gun. By the end of 1783, several galleries, including Windsor Gallery and St George’s Hall, had been completed. The tunnels are now partially open to the public.
