Over the last two decades, there have been many events that are considered acts of terrorism (officially or not), or potential acts of terrorism. Here are some of the more notable instances:
1978-1995 — The Unabomber
Ted Kaczynski, a recluse ideologically opposed to technological progress, sends 16 bombs through the mail over the course of two decades.
1993 — The First World Trade Center Bombing
Ramzi Yousef, a member of al Qaeda and nephew of Khalid Sheikh Mohammed, loaded a truck bomb into the parking garage below Tower 1 of the World Trade Center. He intended for the bomb to bring down the building. It didn't, but it killed six people and injured 1,042. He later wrote to the New York Times, "This action was done in response for the American political, economical, and military support to Israel, the state of terrorism, and to the rest of the dictator countries in the region."
1995 — Oklahoma City Bombing
Timothy McVeigh and Terry Nichols killed 168 and injured more than 600 people when he exploded a car bomb in the Alfred P. Murrah Federal Building in Oklahoma City. McVeigh wanted revenge over the way the government handled the Waco siege in 1993, and thought the destruction of one federal building could spark a revolution. He was sentenced to death.
1996 — Centennial Olympic Park Bombing
At the 1996 summer Olympics in Atlanta, Georgia, Eric Robert Rudolph planted pipe bombs and shrapnel underneath benches in the main square of the Olympic grounds. Two people died; 111 were injured. "Even though the conception and purpose of the so-called Olympic movement is to promote the values of global socialism," Rudolph said in his confession, "as perfectly expressed in the song Imagine by John Lennon, which was the theme of the 1996 Games even though the purpose of the Olympics is to promote these ideals, the purpose of the attack on July 27 was to confound, anger and embarrass the Washington government in the eyes of the world for its abominable sanctioning of abortion on demand."
2001 — 9/11
The deadliest terrorist attack in U.S. history. Nearly 3000 people died.
2001 — The Shoe Bomber
Richard Reid, a British citizen with ties to Al Qaeda, attempted to blow up a plane with explosives implanted in his shoes. After trying to light a fuse to ignite the explosive, Reid was subdued by other passengers.
2001 — Anthrax Attacks
Biologist Bruce E. Ivins mailed letters laced with anthrax to several media organizations and senator's offices. Five people died and 17 others were infected by the lethal bacterium. According to the FBI,Ivins conducted the attacks to bring attention to an anthrax vaccine program he had worked on. While the attacks were conducted in 2001, Ivins wasn't identified as a suspect until 2008.
2002 — The Beltway Sniper
John Allen Muhammad and Lee Boyd Malvo terrorize the D.C.-beltway area, taking shots at people from the modified trunk of a Chevrolet Caprice sedan. Ten people were killed over the course of three weeks. Three others were injured.