During World War II, the best brains in Britain cracked Germany's encrypted secrets but never broke their own code of silence.

Now gray-haired and using walking sticks and at least one wheelchair, the legendary code breakers returned for a reunion Tuesday at Bletchley Park, where they labored in the grim, blacked-out rooms and played a key role in defeating the Nazis.

The code breakers who worked here in anonymity helped alter history, frustrating Adolf Hitler's ambitions by giving Prime Minister Winston Churchill and his wartime Cabinet crucial advance knowledge of Germany's invasion plans, defenses, and U-boat movements.