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Gibraltar's Great Siege Tunnels; courtesy
Gibraltar's Great Siege Tunnels; courtesy

17 Photos That Show the Secret Tunnels of Gibraltar Are a Must-Visit

Picture of Mark Nayler
Updated: 21 September 2017
The Great Siege and Secord World War Tunnels are Gibraltar’s two most fascinating attractions. Comprising 35 miles of subterranean corridors, halls and storage spaces, this extensive network was dug between the 18th and 20th centuries and at one time housed a mini-city. These 17 incredible photos show that Gibraltar’s secret tunnels are a must-visit.

The Great Siege Tunnels are named after the Great Siege of Gibraltar, which was launched by Spanish and French forces in 1789 in an attempt to recapture the territory from Britain. Gibraltar’s defenders built the tunnels on the order of Governor General Eliot, who intended them as a means of installing guns in an otherwise inaccessible part of the Rock. Work began in May 1782.

Entrance to the Great Siege Tunnels; courtesy

Lifelike models in the tunnels demonstrate the cramped working conditions in which they carved by hand into the rock. Nevertheless, progress was rapid and in just two weeks a team of eight workers had excavated 25 metres of tunnel.

Lifelike models in the Great Siege Tunnels; courtesy

The first tunnels were dug purely by hand with the aid of sledgehammers and crowbars. Explosions were occasionally used to blast through particularly difficult stretches.

25 metres of tunnel was dug in just two weeks; courtesy

As you wander around these sometimes-claustrophobic corridors, remember that in total there are 35 miles of tunnels in the Rock – more than twice the length of Gibraltar’s road network.

There are 35 miles of tunnels in the Rock; courtesy

Working conditions quickly became suffocating in the tunnels, so holes were blasted in the side to provide fresh air and ventilation. The soldiers quickly realised that these openings were perfect for the mounting of guns.

Ventilation holes were used to mount guns in the tunnels; courtesy

Throughout the attraction, life-sized models make you feel as if you’re back in 1782, right in the thick of the fighting during the Great Siege of Gibraltar.

Lifesized models bring to life the fighting; courtesy

The slightly eerie figures also present you with panels explaining the purpose of the various tunnels and caverns.

Helpful panels explain the function of the various spaces and tunnels; courtesy

In 1783 the siege ended, with Spain and France having failed to take the Rock from the British. By this time, 113 metres of tunnel had been excavated and four guns mounted in openings along its length. Wandering the tunnels today, you can only imagine how physically demanding the work must have been.

The darker sections of the tunnels can be a little spooky; courtesy of

Work on the subterranean network continued after the siege had finished. This is when St George’s Hall was excavated – a spacious cavern in which a battery of seven guns could be accommodated.

St George’s Hall in the Great Siege Tunnels; courtesy

Some of the tunnels dug into the Rock were actually used as roads.

Some of Gibraltar’s tunnels were in fact underground roads; Philip Lange/shutterstock

The tunnels provided Gibraltar’s British defenders with superb views out to sea and towards the Spanish mainland, making the task faced by their assailants at the end of the Great Siege truly formidable. Today, there are also spectacular views of Gibraltar’s airport.

Stunning views of Gibraltar airport from the Great Siege Tunnels; trabantos/shutterstock

The defeated commander of the Spanish and French troops was taken to see the tunnels after the Great Siege ended (quite a kick in the teeth, you imagine). Awed by their ingenuity, he apparently remarked that they could have been built by Romans.

Models show how a gun would have been operated in the Great Siege Tunnels; courtesy

During the Second World War, Gibraltar’s network of secret underground tunnels was substantially extended. To the seven miles of tunnels that had been dug during and after the Great Siege almost 200 years before, a further 18 miles of subterranean corridors were added.

Gibraltar’s Great Siege tunnels were greatly expanded during WWII; courtesy

Unlike during the Great Siege, the work was carried out with the help of machinery during WWII. Still, the work was punishing and required great precision. It was undertaken by specialist workers from the Royal Engineers and Canadian Army.

A section of Gibraltar’s WWII tunnels; courtesy

The WWII tunnels were expanded in order to accommodate a 16,000-strong garrison and all their weapons and supplies. Tunnels were also needed to link a new military base on Gibraltar’s south-east corner with existing HQs on the western side.

WWII machinery and guns in the tunnels; courtesy

In addition to the garrison and all their supplies, the WWII tunnels contained a telephone exchange and water distillation facility, as well as workshops in which vehicles and guns could be repaired.

The WWII tunnels housed gun repair workshops; courtesy

The two central thoroughfares of the WWII tunnels were Fosse Way and the Great North Road: both ran north-south for almost the entire length of the Rock and connected the network of small tunnels running from east to west.

Specialist workers from the Royal Engineers and the Canadian Army dug the WWII tunnels; courtesy

Great Siege and WWII Tunnels, Gibraltar +350 200 74950