2000s mass murders in the United States

The September 11 attacks, colloquially known as 9/11, were a coordinated series of suicide attacks perpetrated by the Islamist terrorist organization al-Qaeda against the United States in 2001. Nineteen terrorists hijacked four airliners, then flew one into each of the Twin Towers at the World Trade Center in New York City. The third plane crashed into the Pentagon, the headquarters of the United States Department of Defense, in Arlington County, Virginia. The fourth plane crashed in a rural Pennsylvania field during a passenger revolt. In response to the attacks, the United States launched the global war on terror, seeking to eliminate hostile groups deemed terrorist organizations, and the governments purported to support them. This foreign policy agenda was conducted over the next two decades.

9/11 hijacked passenger flight, hit the North Tower of the World Trade Center

shooting on the campus of Virginia Polytechnic Institute and State University in Blacksburg, Virginia, United States

United Airlines Flight 93 was a domestic scheduled passenger flight that was hijacked by four Al-Qaeda terrorists on the morning of Tuesday, September 11, 2001, as part of the September 11 attacks. The hijackers planned to crash the plane into a federal government building in the national capital of Washington, D.C. The mission failed when the passengers fought back, forcing the terrorists to crash the plane in Shanksville in Somerset County, Pennsylvania, preventing them from reaching Al-Qaeda's intended target, but killing everyone aboard the flight. The airliner involved, a Boeing 757-200 with 44 passengers and crew, was flying United Airlines' daily scheduled morning flight from Newark International Airport in New Jersey to San Francisco International Airport in California, making it the only plane hijacked that day not to be a Los Angeles–bound flight.

2001 hijacking of an airliner and subsequent deliberate crash into The Pentagon in Virginia, USA

mass murder that took place on November 5, 2009

series of coordinated shootings in October 2002 in the United States

2006 school shooting in Lancaster County, Pennsylvania

school shooting in 2005

school shooting on Valentines Day, 2008

mass shooting in Omaha, Nebraska, USA

2009 shooting in the US

American serial killer

2008 murder–suicide