Tunnels of Gibraltar

The first tunnels, excavated in the late 18th century, served as communication passages between artillery positions and housed guns within embrasures cut into the North Face of the Rock.

The 20th century saw by far the greatest extent of tunnelling when the Rock was turned into a huge underground fortress capable of accommodating 16,000 men along with all the supplies, ammunition and equipment needed to withstand a prolonged siege.

Since then, the tunnels have progressively been turned over to the civilian Government of Gibraltar, although a number are still owned by the Ministry of Defence and some have been sealed off entirely as they are now too dangerous to enter.

These consisted of trenches cut into the solid rock or natural ledges which were made more defensible by building masonry walls and scarping the cliffs below.

It was intended to reach a position called the Notch, which was inaccessible by any other route, where the British garrison sought to install a new artillery battery to cover a blind angle.

By the end of the siege, the newly created Upper Gallery housed four guns, mounted on specially developed "depressing carriages" to allow them to fire downwards into Spanish positions on the isthmus to the north.

The Notch was not reached until after the siege had ended; instead of mounting a gun above it, the outcrop was hollowed out to create a broad firing position called St George's Hall.

[8] These comprised: The second phase of tunnelling was driven by a number of disparate requirements towards the end of the 19th century as Gibraltar's naval base became a key strategic asset for the United Kingdom.

[5] In 1895, the Army dug out two natural caves under Windmill Hill to create an underground ammunition store, the Beefsteak Magazine.

In 1901, the Admiralty followed up by extending the natural Ragged Staff Cave to form a tunnelled underground magazine adjoining the harbour.

They were supplied with rainwater gathered from catchment areas on the Great Sand Dune on the east side of the Rock and conveyed to the reservoirs by a new east–west tunnel.

An additional reservoir was begun but was used, in its incomplete state, as a storehouse and barracks for 4th Battalion the Black Watch during the Second World War.

[9] The most intensive phase of tunnelling in Gibraltar's history came during the Second World War, when the territory played a vital role in the North Atlantic and Mediterranean theatres.

Numerous new tunnels were excavated to create accommodation for the expanded garrison and to store huge quantities of food, equipment and ammunition.

Within the tunnels there were also an underground telephone exchange, a power generating station, a water distillation plant, a hospital, a bakery, ammunition magazines and a vehicle maintenance workshop.

Bill Pointon was working with Harry Calligan on the tunnel face when they drilled into a pill of powder that had not been "fired" in the previous shift.

Excavation was slow, at a rate of only about 200 metres (660 ft) per year, but the methods used by the original tunnellers had the advantage of causing only minimal damage to the surrounding rock.

[11] Others have needed to be supported by rock bolts, weld mesh, props, arches or tunnel linings, and their integrity is monitored by carrying out scanline surveys.

[19] One of the most distinguished occupants was General Dwight D. Eisenhower, who used the tunnels as his headquarters for the invasion of North Africa – Operation Torch – in November 1942.

The subterranean passages under the Rock provided the sole available office space, and in them was located the signal equipment by which we expected to keep in touch with the commanders of the three assault forces.

Damp, cold air in block-long passages was heavy with a stagnation that did not noticeably respond to the clattering efforts of electric fans.

Most of the Second World War and post-war tunnels are closed to the public – some, notably AROW Street, have been sealed off altogether as being too dangerous to enter.

[24] Two of the post-war tunnels, Keightley Way and Dudley Ward Way, are open to civilian vehicle traffic to facilitate journeys between the west and south of Gibraltar, and along the precipitous east coast of the peninsula.