Several suspected bombings were discovered and thwarted since 2001.
Terrorist Attacks on U.S. Homeland, September 11, 2001:
Two hijacked airliners crashed into the twin towers of the World Trade Center. Soon thereafter, the Pentagon was struck by a third hijacked plane. A fourth hijacked plane, suspected to be bound for a high-profile target in Washington, crashed into a field in southern Pennsylvania. The attacks killed 3,025 U.S. citizens and other nationals. President Bush and Cabinet officials indicated that Usama Bin Laden was the prime suspect and that they considered the United States in a state of war with international terrorism. In the aftermath of the attacks, the United States formed the Global Coalition Against Terrorism.