In 2002 the first Hellfire missile was shot from a U.S.-operated drone at suspected terrorists in Yemen. Since then an estimated 480 more unmanned airstrikes have been carried out by the Central Intelligence Agency and the Department of Defense. According to the Bureau of Investigative Journalism, which used data from news outlets, field investigations, and evidence submitted in legal cases, the strikes have killed at least 3,136 people, among them 555 civilians, including 185 children. The State Department declined to comment on those figures; others in Washington give a range of numbers. In February, Senator Lindsey Graham (R-S.C.) said drones have killed 4,700 people. Senator Dianne Feinstein (D-Calif.) cited civilian casualties in the single digits. On May 22, Attorney General Eric Holder acknowledged four of the five Americans, including Anwar al-Awlaki, killed in U.S. drone strikes. The attacks, which have decimated al-Qaeda-aligned groups, declined after 2010. Here, for the first time, is a comprehensive compilation of all known lethal U.S. drone attacks. President Obama is scheduled to address the legality of this undeclared aerial war on May 23.