For over 200 years, Ordnance Survey has mapped every square mile of the British Isles, capturing not just the contours and geography of our nation, but of our lives. Originally intended for military use, OS maps were used during wartime to help locate enemy positions. In peacetime, they helped people discover and explore the countryside. Today, the large fold-out paper maps, used by generations of ramblers, scouts and weekend adventurers, represent just a small part of the OS output. As Ordnance Survey adjusts to the digital age, Timeshift looks back to tell the story of a quintessentially British institution.