Currently improvised explosive devices (IEDs) are the number one killer of US troops in Iraq. Soldiers from the 1st Brigade Combat Team, 4th Infantry Division, from Fort Hood, Texas, take part in complex war games at the U.S. Army's National Training Center at Fort Irwin in the California's Mojave Desert. Soldiers receive the most realistic training possible for defeating IEDs, roadside bombs, vehicle bombs and even terrorists laden with suicide vests before deploying to Iraq and Afghanistan.