CAT WALK U.S. Army Master Sgt. Ralph Chisolm transits an obstacle course in Arta Beach, Djibouti, Oct. 18, 2008. Chisolm is assigned to the 2nd Battalion, 18th Field Artillery Regiment, Combined Joint Task Force - Horn of Africa. More than a dozen servicemembers assigned to CJTF-HOA participated in an annual three-week course hosted by members of the 13th Demi-Brigade, French Foreign Legion. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 965058-U-RHL17-312.jpg Photo Gallery