Sometimes truth really is stranger than fiction.
During World War II, The United States Playing Card Company joined forces with American and British intelligence agencies to create
a very special deck of cards. They gave out the cards as Christmas gifts to help allied prisoners of war escape from German POW camps. The map was concealed between the two layers which formed a playing card. Once submerged in water, the POW would peel off those layers and find a part of the map on each card. Then he would assemble the parts and voila―a functioning map of his area!
