In some of the bloodiest fighting of the war, Al-Qaeda attacked several Shiite holy sites Baghdad and Karbala in March 2004. In the city of Fallujah, four U.S. military contractors were killed, their bodies burned and hung from a bridge. The murders, which were relayed around the world, led to a U.S. and Iraqi-led mission against insurgents in the city. Among the dead are 38 U.S. troops, 1,200 insurgents and 800 Iraqi civilians.
(Photo: REUTERS/Ako Rasheed)