On Sept. 11, 2012, in Benghazi, Libya, 150 gunmen attacked the American diplomatic mission.
The death toll included three U.S. diplomats.
Hillary Clinton is blamed by some Republicans.
They say the attack could have been prevented had she provided increased security.
On Oct. 23, 1983, in Beirut, Lebanon, two suicide bombers drove their explosive laden trucks into a U.S. Marine barracks.
The death toll included 220 Marines, making this incident the deadliest single-day death toll for the United States Marine Corps since World War II.
President Ronald Reagan was not blamed, but investigators said the attack could have been prevented if the barracks guards carried loaded weapons and if barriers had been erected to prevent the bombers from driving their trucks into the barracks.