Via Steven Pressfield’s blog post
A Ghurka rifleman escaped from a Japanese prison in south Burma and walked six hundred miles alone through the jungles to freedom. The journey took him five months, but he never asked the way and he never lost the way. For one thing he could not speak Burmese and for another he regarded all Burmese as traitors. He used a map and when he reached India he showed it to the Intelligence officers, who wanted to know all about his odyssey. Marked in pencil were all the turns he had taken, all the roads and trail forks he has passed, all the rivers he had crossed. It had served him well, that map. The Intelligence officers did not find it so useful. It was a street map of London.