People across the United States are marking 25 years since the September 11 attacks. On 11 September 2001, almost 3,000 people died when members of the terrorist group al-Qaeda hijacked four planes. Two planes crashed into the Twin Towers in New York City, one hit the Pentagon near Washington, and one crashed in Pennsylvania.

This attack happened because al-Qaeda wanted to cause harm to the United States and spread fear. The group carefully planned these attacks to target important buildings and kill many people.

Now, many ceremonies are taking place to remember the victims. Families and friends gather at the three sites where the planes crashed. They read the names of the victims and stand in silence. This day is also very important for people born after 2001, as they learn about the event in school and from their families, to make sure the tragedy is never forgotten.