Did you know... During the Cold War, Soviet cartographers intentionally inserted subtle errors and discrepancies into their maps as a way to detect and identify unauthorised copies or leaks. These errors, known as "trap streets" or "paper towns," would include nonexistent towns, rivers, or roads that would not be present in genuine Soviet maps. If a map with these intentional errors appeared in the hands of foreign intelligence agencies or unauthorised individuals, it would indicate that the map had been copied without permission. This technique was used to safeguard sensitive military and strategic information and maintain the security of Soviet cartographic materials.NB: One of our personal favourites is this amazingly detailed map of San Diego created by Soviet spies.
