In 1893 work began on building a new harbour for Gibraltar which needed to be able to accommodate and service the expanding Royal Navy. Stone was needed and this was brought from the East side of the Rock. Rather than go though the exercise of loading and unloading ships, a tunnel was dug straight through the Rock from West to East. The tunnel was then used to operate a narrow gage railway which could bring the fill directly to the harbour. Apart from the Water Works Tunnels, this is the only extensive tunnelling carried out during the Victorian Period.
During World War 2 a large command and control centre was built off the main tunnel and this was to remain in use until the 1980’s, latterly as a NATO COMCEN.
During WW2, one of the rooms in the command centre was used by Dwight Eisenhower and he has been photographed sat there. He commanded Operation Torch from this location, the invasion of North Africa.
The whole facility is now leased by Continent8, a data storage company, http://www.continent8.com/, who state how secure it is some 500 metres underground.