NEW YORK — On Sept. 11, 2001, 19 members of the Islamic extremist group al-Qaeda hijacked four airplanes and carried out attacks against several targets in the United States, killing nearly 3,000 people.
Two planes were flown into the World Trade Center in New York City, a third plane hit the Pentagon near Washington D.C. and the fourth crashed into a field in Shanksville, Pennsylvania.
Thousands more were injured that day, while many first responders and civilians who were working or were around the toxic conditions continue to deal with health issues 20 years later.
The crash sites represented the largest crime scene in FBI history, according to the organization.
The attacks prompted the United States to increase its efforts to combat terrorism, considered to be the gravest threat against the country.
The 9/11 attacks forever changed the world, becoming one of the most pivotal moments in American history.
Below you’ll find a timeline of the events that occurred: