Pearl Harbor

Ten hours before the attack on December 7, 1941, Americans intercepted a 14-part Japanese message. It was deciphered at 4:37 am, just hours before the attack, but it remained in the code room. Three hours later it was delivered to President Franklin Roosevelt. By the time the deciphered message was transmitted to the Pacific, the receiver was not working. The attack cost 3400 lives. The message was delivered to Pearl Harbor three hours after the attack.