The sneaky Christmas gift for WWII POWs

Soldiers play cards. It’s true today and during World War II, especially for soldiers held captive.

Knowing that the U.S. and British intelligence agencies devised a top-secret plan that violated the Geneva Convention to help POWs escape: Playing cards with a secret map of escape routes.

The cards looked like ordinary blue Bicycle playing cards and were distributed to POWs in Christmas parcels from the Red Cross.

Ordinary playing cards are made by gluing two layers of paper together. But when these secret map cards were submerged in water, the layers would peel apart to reveal a portion of a map. Once all the cards were peeled, POWs could assemble them to form a functioning map of the region, with included escape tips. According to Popular Mechanics, these sneaky decks had a cellophane seal intentionally applied crookedly.

The scheme actually did help some prisoners escape. About 32 POWs — mainly high-value detainees like pilots and officers — successfully escaped Castle Colditz, the notorious prison camp for “incorrigible” Allied troops. Some speculate that before these troops departed, they were given hints that something from home could help them escape, but they were not told the details.

According to War History Online, the supposedly escape-proof Colditz saw more than 300 total escape attempts.

The secret playing card operation, carried out around 1944, was not widely known until the 1970s.

In the 1990s, the United Playing Card Company created a commemorative Bicycle Escape Map playing card set, available today, with the map printed on the suit side of the card, so you don’t have to destroy the card.

You can see the original deck at the International Spy Museum in Washington, D.C.