ARLINGTON TRIBUTE Army Chief of Staff Gen. George Casey and Army Secretary Pete Geren place a wreath at the Tomb of the Unknowns as part of the Army's 233rd birthday tribute at Arlington National Cemetery, Va, June 14, 2008. The U.S. Congress adopted "the American continental army" on June 14, 1775. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 618531-V-KKZ59-189.jpg Photo Gallery