Name at birth: Ahmed Fadeel Nazal al-Khalayleh

Abu Musab al-Zarqawi was the most prominent leader of the insurgency against the United States' occupation of Iraq until he was killed by U.S. forces in June 2006. Born in poor circumstances in Jordan and jailed there for petty crimes in the 1980s, he became a militant Islamist and fought against the Soviet Union in Afghanistan. He later was accused of plotting attacks on tourist sites in Jordan and finally resurfaced in Iraq as the head of a group called "Tawhid and Jihad." The group was known for attacks on Shiites and beheadings of foreign hostages, which it documented and released on videotape. In 2004 he aligned the group with Osama bin Laden's al-Qaeda, an international terrorist organization. He died in an air raid north of Baquba, Iraq.