During operation Overlord, June 6...
Illustration
During operation Overlord, June 6, 1944, plans included the dropping of large elements of three airborne divisions behind the Normandy beaches shortly after midnight prior to the invasion. These elements of the United States' 82nd and 101st Airborne, plus the 1st Airborne from Great Britain were intended to confuse the enemy and obstruct reinforcements from reaching the beaches during the critical phase of the battle. Since the soldiers would be dropping in the dark, behind enemy lines, it was crucial that they possess some manner of recognition of friendly forces. This recognition was accomplished by the use of passwords and handheld "crickets" (small metal devices that made a loud click). By the response of "thunder" to the challenge of "lightning" or by clicking twice in response to a one-click challenge, the troops had some means of identifying other allied soldiers in the dark.
