The Ghost Army was a United States Army tactical deception unit during World War II officially known as the 23rd Headquarters Special Troops. The 1,100-man unit was given a unique mission within the U.S Army: to impersonate other U.S. Army units to deceive the enemy. From a few weeks after D-Day, when they landed in France, until the end of the war, they put on a “traveling road show” utilizing inflatable tanks, sound trucks, fake radio transmissions and pretence. They staged more than 20 battlefield deceptions, often operating very close to the front lines.
The unit consisted of the 406th Combat Engineers (which handled security), the 603rd Camouflage Engineers, the 3132 Signal Service Company Special and the Signal Company Special.