J. Christopher Stevens, the U.S. ambassador to Libya, was killed Tuesday in the attack on the U.S. consulate in the eastern city of Benghazi by protesters angry over a film that ridiculed Islam's Prophet Muhammad.

According to the State Department Office of the Historian, five U.S. ambassadors have been killed by terrorists:

—Adolph Dubs, in Afghanistan, 1979

—Francis E. Meloy Jr., in Lebanon, 1976

—Rodger P. Davies, in Cyprus, 1974

—Cleo A. Noel Jr., in Sudan, 1973

—John Gordon Mein, in Guatemala, 1968

Two other U.S. ambassadors have died in plane crashes:

—Arnold L. Raphel, in Pakistan, 1988

—Laurence A. Steinhardt, in Canada, 1950