Lt. Col. Mario Diaz, a native of Sierra Madre, Calif., talks to an Iraqi army soldier and a Sons of Iraq (Abna al Iraq) volunteer at a joint checkpoint in Nassir Wa Salam, west of Baghdad, April 24. The checkpoint is one of the many places that the Iraqi army and the Sons of Iraq can be seen working together to maintain a secure environment and continue rebuilding the nation of Iraq. Diaz is the commander of the 1st Battalion, 21st Infantry Regiment "Gimlets," 2nd Stryker Cavalry Regiment, Multi-National Division – Baghdad. (U.S. Army photo/Spc. Dustin Weidman, 21st Infantry Regiment, 2nd Stryker Cavalry Regiment)