The United States Playing Card Company collaborated with American and British intelligence agencies during World War II to produce a unique deck of cards. This particular deck, known as the "map deck," was designed to aid Allied prisoners of war in escaping from German POW camps. Ingeniously, the maps of top-secret escape routes were concealed between the paper layers of the playing cards, allowing them to be easily peeled apart when soaked in water. This covert deck proved crucial in helping prisoners find their way to safety.
