NEW YORK — Americans are marking 24 years since the Sept. 11, 2001, attacks with solemn ceremonies, volunteer work and other tributes honoring the victims.
Many loved ones of the nearly 3,000 people killed will join dignitaries and politicians at commemorations Thursday in New York, at the Pentagon and in Shanksville, Pennsylvania.
https://en.wikipedia.org/wiki/September_11_attacks
The September 11 attacks,[f] also, often colloquially, known as 9/11,[g] were four coordinated Islamist terrorist suicide attacks by al-Qaeda against the United States in 2001. Nineteen terrorists hijacked four commercial airliners, two of which were flown into the Twin Towers of the World Trade Center in New York City and the third into the Pentagon, which is the headquarters of the U.S. Department of Defense, in Arlington County, Virginia. The fourth plane crashed in a rural Pennsylvania field, at the site of the present-day Flight 93 National Memorial, during a passenger revolt. In response to the attacks, the United States waged the global war on terror over multiple decades to eliminate hostile groups deemed terrorist organizations, as well as the governments purported to support them.