History Today, June 6: The role of signals intelligence or 'ULTRA' on D-Day (opens in new tab)

The term D-Day was a shorthand expression first used in World War I to denote the date an operation was to be launched. In the earlier war, officers also used H-HOUR and M-MINUTE, but these were seldom used in World War II. Because of the scope of the 1944 operation and the momentous stakes, in common parlance, “D-Day” has come to refer primarily to the landings in Normandy. <br /> <img src='https://media.defense.gov/2024/Jun/04/2003478139/150/150/0/440606-D-IM472-1540.JPG' alt='U.S. Soldie...