Anti-government domestic terrorist Timothy McVeigh detonated a truck bomb at the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma. The explosion killed 168 people, including nineteen children.

Congress passed the USA Patriot Act (Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism). The act provided law-enforcement agencies and the Justice Department more power in investigating and dealing with suspected terrorists, loosened constraints on wiretaps and internet monitoring, and allowed for the detainment and deportation of non-citizens believed to pose risks to national security. The act proved controversial as many viewed its measures as unconstitutional infringements on...

Letters contaminated with anthrax spores, mailed from Trenton, New Jersey, were sent to various news organizations and government offices. The anthrax ultimately caused the deaths of five people. No one was ever convicted of the mail attack, though the Department of Justice issued a report in 2010 that held government microbiologist Bruce Ivins responsible. Ivins had committed suicide in 2008.

On Tuesday, September 11, 2001, terrorists executed a series of attacks masterminded by al-Qaeda leader Osama bin Laden. At 8:46 a.m., a hijacked plane crashed into the North Tower of the World Trade Center in New York City. A second plane crashed into the South Tower at 9:03 a.m. At 9:37 a.m., a third plane hit the Pentagon in Washington, DC. At 10:03 a.m., passengers on a fourth hijacked plane caused it to crash in a field near Shanksville, Pennsylvania, before the hijackers could fly it to its intended target, likely Washington, DC....