Combat history of the U.S. Army's oldest armored regiment Tank battles in North Africa, Sicily, Normandy, and the Battle of the Bulge The 66th Armored Regiment is still active today and has served in Iraq From its baptism of fire in the mud of the Western Front in 1918 to its triumphant march into Berlin in July 1945, this is the story of the U.S. 66th Armored Regiment. It was the only American heavy tank unit to see combat in World War I, and between the two wars, the regiment served as a laboratory for new ideas and equipment. After training under Gen. George S. Patton, the 66th distinguished itself in numerous battles during World War II, earning six battle streamers for the unit and a Medal of Honor for one of its officers.