A look back: Terrorist acts against Americans

A U.S. Marine sits on the bumper of a car that was destroyed when a huge bomb explosion wrecked the American Embassy in West Beirut, April 19, 1983, where he is on guard duty across the street from the Embassy. Rescue workers continued to search the rubble for those missing in Monday's explo…

A look back: Terrorist acts against Americans

A U.S. Marine stands guard as rescue workers search the rubble of the U.S. Embassy in Beirut for bodies. Rescue workers search the collapsed front of the building after the terrorist bombing on April 18, 1983. (AP Photo/Bill Foley)

A look back: Terrorist acts against Americans

Rescuers continue to probe the wreckage of the U.S. Marine command, Monday, Oct. 24, 1983 in Beirut building that was destroyed on Sunday by a terrorist bomb. In the background can be seen the control tower of the Beirut airport. (AP Photo/Zouki)

A look back: Terrorist acts against Americans

Destroyed autos and debris still litter the B-2 level of New York's World Trade Center, March 7, 1993. Explosives experts used scaffolding to lower themselves into a giant bomb crater under the building, expanding their search for new clues after the shaken cellar was strengthened with steel…

A look back: Terrorist acts against Americans

A gaping hole caused by an explosion in an underground garage at New York's World Trade Center reveals various levels of parking beneath the twin towers complex, March 8, 1993. New steel beams were added over the weekend to help shore up the center's shaken foundation. (AP Photo/Richard Drew)

A look back: Terrorist acts against Americans

This is the glass door of the lounge of the Fiumicino Airport in Rome, Italy, which was smashed by the Arab terrorists who then headed for the Pan American jetliner, in background on tarmac, in a shooting spree, Dec. 17, 1973. (AP Photo)

A look back: Terrorist acts against Americans

Workers clear debris in an underground corridor in the World Trade Center in New York, March 1, 1993. At least five people were killed in the explosion that the FBI confirmed was caused by a bomb. (AP Photo/Alex Brandon)

A look back: Terrorist acts against Americans

A U.S. Marine wears a gas mask after rescue workers using a backhoe broke open a stock of tear gas that had been stored in the Embassy, April 19, 1983. Tear gas drifted up through the rubble, causing rescue workers and Marines to cough and sneeze. The Embassy, seen in the background, was sev…