The 442nd Infantry Regiment (Japanese: 第442歩兵連隊) was an infantry regiment of the United States Army. The regiment is best known as the most decorated in U.S. military history and as a fighting unit composed almost entirely of second-generation American soldiers of Japanese ancestry (Nisei) who fought in World War II. Beginning in 1944, the regiment fought primarily in the European Theatre, in particular Italy, southern France, and Germany. The 442nd Regimental Combat Team (RCT) was organized on March 23, 1943, in response to the War Department's call for volunteers to form the segregated Japanese American army combat unit. More than 12,000 Nisei (second-generation Japanese American) volunteers answered the call. Ultimately 2,686 from Hawaii and 1,500 from U.S. concentration camps assembled