Let us never forget the bombing of the US Marine barracks in Beirut, Lebanon, on this date in 1983.
In the attack on the building serving as a barracks for the 1st Battalion 8th Marines (Battalion Landing Team - BLT 1/8), the death toll were 220 Marines, 18 sailors, and three soldiers, making this incident the deadliest single-day death toll for the United States Marine Corps since World War II's Battle of Iwo Jima, the deadliest single-day death toll for the United States Armed Forces since the first day of the Vietnam War's Tet Offensive, the deadliest single terrorist attack on American citizens in general prior to the September 11 attacks, and the deadliest single terrorist attack on American citizens overseas. Another 128 Americans were wounded in the blast. Thirteen later died of their injuries, and they are numbered among the total number who died. An elderly Lebanese man, a custodian/vendor who was known to work and sleep in his concession stand next to the building, was also killed in the first blast. The explosives used were later estimated to be equivalent to as much as 9,525 kg (21,000 pounds) of TNT.
There's much more at the link.
In the immortal words of Robert Laurence Binyon:
They shall grow not old, as we that are left grow old:
Age shall not weary them, nor the years condemn.
At the going down of the sun and in the morning
We will remember them.