The Great North Road is part of the immense tunnel system beneath Gibraltar. It was constructed between 1942 and 1943 as a main north-south communications route, large enough to carry lorry traffic.
As well as providing a through route,there are many side chambers which were used for accommodation (often in Nissen Huts), kitchens, magazines, hospitals, storage and power generation. To aid navigation, various locations along the tunnel are named after towns and cities on the orginal Great North Road. These are in the correct order so Doncaster lies between Peterborough and Durham for example.