It would seem that during the Second World War, the British constructed a 'Top Secret' system of chambers inside the Rock of Gibraltar.
The idea was that, if the Germans ever managed to capture Gibraltar, six men would seal themselves in these chambers and from there they would secretly monitor and report to London the movements of the enemy.
Naturally, the chambers were never used and remained sealed for over fifty years until the Gibraltar Caving Group re-discovered them at the end of 1997, when along with the Spanish team GIEX they conducted a survey of the site under the supervision of the Gibraltar Museum. The chambers were in a well-preserved state and included dormitory facilities, east - and west-facing observation posts as well as a fresh-water cistern. In September 1998, Mr Dennis Woods, who had been involved in the construction of the secret chambers, which in those days were known as Braithwaite's Cave, after the Commanding Officer's name, returned to Gibraltar for the first time in over fifty years and confirmed the authenticity of this unique site.