You may have seen old films about captured soldiers, sailors and airmen (POWs) trying to escape from the camps they were put in. This map was made by British prisoners in a German camp.

A high level of detail was very important if you were planning to escape because you were risking your life. By looking carefully at the map you can see the barbed wire around the prisoners' huts, the football pitch for recreation and the railway station. You can also see which towns the roads lead to, and even the direction the river flows.

Just as important as detail was scale, which you can see on the left-hand side. The scale would help you to work out how far and how long it would take you to run or creep from one place to another.