Rare look inside secret ‘last bastion’ maze of bomb-proof tunnels built to defend Brit outpost from Nazi invasion 

AS NAZI bombs rained down on enemy nations, officials in Britain's strategic territory of Gibraltar knew they had to act fast. What transpired was an incredible labyrinth of secret bomb-proof tunnels dug inside The Rock to safely house soldiers and equipment. It became an almost hidden city - with everything 16,000 troops needed to survive...