(CNN) -- Here is a look at what you need to know about the 1983 bombing at a Marine compound in Beirut, Lebanon that killed 241 U.S. service personnel.
Facts: October 23, 1983 - 241 U.S. service personnel, 220 Marines and 21 other service personnel, are killed by a truck bomb at a Marine compound in Beirut, Lebanon.
300 service members had been living at the four-story building at the airport in Beirut. There were 1,800 Marines stationed in Beirut at the time.
A multi-national force with units from France, Italy and the United Kingdom is also on peacekeeping duty in Lebanon at the same time.
At the same time the Marine barracks is hit, a suicide bomber drives a pickup truck full of explosives and crashes into a building housing French paratroopers. Approximately 58 French soldiers are killed in the attack.
This is the most deadliest attack against U.S. Marines since the battle over Iwo Jima in February 1945.
The bombing is traced to Hezbollah, a militant and political group that originated in Lebanon in 1982. Iranian and Syrian involvement was also suspected.
The Marines are criticized for having lax security at the barracks.
The commander of the barracks, Col. Timothy J. Geraghty, says in congressional hearings investigating the attacks that the compound was hard to defend because it was on flat ground and vehicles drove by it daily to access the airport.
Timeline: 1982 - President Ronald Reagan sends Marines to Lebanon on a peacekeeping mission.
October 23, 1983 - At 6:22 am, a truck carrying 2000 pounds of explosives drives into the Marine compound in Beirut, Lebanon and crashes into the 1st Battalion, 8th Marine Regimental Battalion Landing Team barracks.
February 1984 - U.S. troops withdraw from Lebanon.
1985 - The Inman Report is released. It finds that Marine officers did not take proper steps to protect the barracks against terrorist attacks.
May 30, 2003 - A U.S. federal judge rules that the terrorist group Hezbollah carried out the attack at the direction of the Iranian government. The ruling allows families of the victims to sue Iran.
September 7, 2007 - U.S. District Judge Royce C. Lamberth orders Iran to pay more than $2.6 billion to survivors and family members.
March 1, 2010 - A lawsuit is filed in New York City seeking to force Iran to pay the $2.6 billion awarded to survivors and family members in 2007.
March 30, 2012 - U.S. District Court judge Royce Lamberth issues a judgment against Iran of $2.1 billion, to be paid to the families and survivors of the attack.