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