With the entry of Italy into the War, and a powerful Germany dominating Europe, the strategic importance of Gibraltar grew. The problem of storage was urgent and vital; space became even more valuable; stores, food, and equipment had to be built up and protected, and siege accommodation was required for the troops. A tunnel system would meet these needs, and would give full protection from the then known types of air attack, as well as from sea and land bombardment.
At the start of the war, the civilian population was evacuated and the garrison was greatly increased in size. Numerous new tunnels were excavated to create accommodation for the expanded garrison and to store huge quantities of food, equipment and ammunition. The tunnelling was carried out by four specialised tunnelling companies from the Royal Engineers and the Canadian Army.
A new Main Base Area was established in the south-eastern part of Gibraltar on the Mediterranean coast, shielded from the potentially hostile Spanish mainland, and new connecting tunnels were created to link this with the established military bases on the west side. A pair of tunnels the Great North Road and the Fosse Way, were excavated running nearly the full length of the Rock to interconnect the bulk of the wartime tunnels.
The tunnels accommodated what amounted to an underground city. The entire 16,000-strong garrison could be housed there along with enough food to last them for 16 months. 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. The total length of the entire tunnel network inside the Rock is approximately 34 miles, 55 kilometres.
Licensed tour guides will take you on a tour lasting approximately 30 - 40 minutes and include static exhibitions and photographic displays. Tours run Monday to Sunday from 09:30 – 19:15 (last entry 18.15).